A Fully Enclosed Chaincase That Works

[Andre Jute]

A FULLY ENCLOSED CHAINCASE THAT WORKS
Part 1

I have fully enclosed chaincases on three of my bikes and seven years of experience -- about 7000 miles -- with them.

THERE IS NO SUCH THING AS AN OIL BATH!
No chaincase I know of is fully enclosed. There is no chaincase which truly meets the common description of "the chain runs in an oil bath". Considering that one function of oil and wax is to carry crud out of the chain, I'm not so certain I would want the chain to recycle that oil, which would certainly happen in an "oil bath" if someone could build such a thing on a bicycle.

So here we're talking about fully enclosed chaincases in the full knowledge that they aren't truly fully enclosed. All of them have holes of one kind or another.

KINDS OF CHAINGUARDS AND CHAINCASES
Chainguards can be anything from a bash guard protecting the chainwheel against stones and the cyclist's pants legs against oil, through channels running nearly the full length of the chain on the topside, to chaincases that surround the drivetrain including the chain. This mini-article is about the full or surround chaincases, plus the Hebie Chainglider which surrounds the chain but leaves the rest of the drivetrain visible.

Note also that all the chaincases under discussion are for use with internal hub gearboxes; no derailleurs need apply. I have tested the chaincases I discuss with various Shimano 8-speed hub gearboxes and the Rohloff Speedhub 14. Hub gearboxes with torque arms or other projections or brakes on the drive side will almost certainly not fit. Shimano and Rohloff have only the sprocket (or in the case of my Shimano Cyber Nexus, a thin, small stepper motor for the automatic gearchange) on the drive side; the brakes and torque reactors fit to the other side.

WHAT ARE WE TALKING ABOUT
It seems to me that a chain protector must do more than just keep oil off your legs; it must also protect the drivetrain against excessive wear. So we'll stick to the full or surround chaincases.

1. Metal chaincases as on old-fashioned Raleigh sportsters, still faithfully copied in India (and possibly by Pashley). I have no recent experience of these and they would be too crude for my sort of bike, and too noisy and heavy for the tourers here.

2. Plastic surround chaincases as fitted to many Dutch bikes. I will discuss these in detail as they are in fact easily available and much more easily fitted than the metal ones above.

3. Chainhugging chaincases like the Hebie Chainglider.

4. Crossover chaincases like Utopia Country, which imports front and rear enclosures from the modern Dutch style (2 above), improves them out of recognition, and mates them with chainhugging pipes imported from recumbent practice.

WHAT'S THE PROBLEM WITH CHAINCASES?
There are three major problems. They are attachment, attachment and attachment. All other problems are minor.

The minor problems include sourcing the chain case and the fact that certain chaincases -- the Chainglider is a notorious example -- limit you very strictly to Hebie's choice of combinations of chainwheel and sprocket, while some can take only 3/32in chains and others (the Country for instance) are so slender there is no space to fit a spider so that the crank must be directly attached to a flat chainwheel.

HEBIE CHAINGLIDER
The Hebie Chainglider is basically a plastic channel that clips around the chain wherever it runs, including across the gearing, and has provision for enclosing the dirty teeth on the back of the chainwheel and the front of the sprocket. It is entirely selfsupporting on the chain and is fitted without tools.

[[[ This is no longer true. Read further on in this thread how easy it is today to buy a Hebie Chainglider in any of the sizes made. The biggest problem with Hebie's Chainglider is Hebie, specifically the maker's trading policy. They do not sell direct, and their dealers cannot make single orders. Thus, while in theory you can buy Rohloff-suitable Chaingliders for chainwheels of 38, 42 and 44 teeth, which all work with the Rohloff sprockets of 15-17 teeth but not the 13 tooth one, in practice you take what the dealer has, which is generally 42 teeth. I have never, not once, seen a 38 tooth Hebie for Rohloff offered for sale anywhere. A dealer who offered to order one for me after nearly three years still has to receive it.]]]

I had a Hebie Chainglider on loan for a while and used it on Shimano 8-speed HGB equipped bike. If there was excessive noise or drag, as others claim, they escaped my notice; people can get hypercritical because they think they must say something critical when they write a review. The Chainglider also seemed to me as durable as one can expect from an item in constant contact with moving metal.

What did concern me a little is that any crud cast off in oil by gravity, any white wax enclosing a speck of dirt and falling off, will be fed back into the chain again because the Chainglider in fact hugs the chain closely.

Hebie's Chainglider seems expensive but when you consider that there are no attachment parts to be sourced, perhaps custom made, it starts to look very reasonable indeed. At a quarter the price of the upmarket Utopia Country chaincase, the Hebie Chainglider looks positively cheap.

DUTCH PLASTIC CHAINCASES
I have these Dutch plastic chaincases on a bike from Royal Dutch Gazelle and from Trek Benelux. I also have a spare of which Trek made me a gift when I complained that the one on the bike, admittedly clearly a prototype, had been crudely cut to permit cable routing. The Gazelle is proprietary design probably made for them by the same people who made the much cruder generic version Trek adapted.

All of these plastic Dutch city bike and citysports (a Dutch touring/utility bike classification -- my Dutch bikes are technically "stadsport fietse") chaincases come in three, four, five or six parts.

All have a backbone that attaches to the chainstay, all have a top and a bottom shell which clip or screw to the backbone; all can be seen to be split along a horizontal line at or near the chainstay.

Some have cutouts over the chainwheel and/or sprocket into which further strictly decorative mouldings clip when the top and bottom shells are assembled around the backbone.

Some chaincases just have a hole in the two shells for the pedal-axle to pass through. These are crude and likely to rattle but you may not care because such a chaincase may avoid other sourcing/fitting problems of suitable bottom brackets and metals brackets.

Some chaincases extend the spine to the bottom bracket, some have a backplate which is held in by the bottom bracket cup against the frame and to which the front of the shells attach. Either requires a bottom bracket designed for chaincase use. These bottom brackets are not hard to come by; you may have held a Shimano bottom bracket of the UN-2x to -9x varieties in your hand and wondered what's the idea of the splitting the spacer in two, or what a single spacer on the drive side is for: well, the thickness of one part of the spacer will correspond to the standard thickness of a chaincase, so you lose one half of the spacer (or the whole spacer if there is only one) and fit the chaincase in its place. That solves half your mounting problem.

SO HOW DO YOU GET ONE OF THESE MAGIG DUTCH CHAINCASES?
The point of these Dutch chaincases for Rohloff-equipped Thorn and other hub gear bike owners wanting chaincases is that these are available in return for only the slight effort of finding a Dutch dealer who will post the thing to you wherever you are. You can even choose your style and colour(s), within reason. There are millions of these chaincases running around on everyday Dutch bikes, and they need replacements, and the manufacturers every now and again sell off surplus. At least theoretically, you can add one of these to your Rohloff-equipped Raven cheaper than a Hebie Chainglider -- and have all the choice in the world of chainwheels and sprockets.

BUT?
Listen up! We have so far only discussed the front mounting of the spine fitting on the chainstay around which the chaincase is built up, and we have discovered that some chaincases do not in fact have a front mounting, merely a hole around the pedal axle.

So, if there is no means of fixing the chaincase spine on the chainstay to the bottom bracket, you might need a bracket on the front of the chainstay, say near the chainstay bridge. This fitting need not be very sophisticated; it can be a stainless steel hoseclip through slots in the chaincase spine and around the chainstay, preferably with a strip of rubber to protect the paintwork.

That's easy enough. Now it gets tough.

All these chaincases -- in the versions known to me anyway -- require a bracket on the frame a few inches short of the frame end around which the rear of the spine for the chaincase can be angled up or down; adjustment is required to line up the chaincase with the sprocket. This is where the big problem starts.

This rear bracket is *not supplied* by the maker of the chaincase. I know this for a fact because I asked Trek where were the brackets to fit the chaincase they gave me, and they told me it was not part of the supply, that in fact the brackets on my (*very* limited edition) bike were manufactured in-house. Still, the bracket can be bent up from a strip of steel; it isn't a big deal if you have a vise (or a sturdy garage corner wall), a pair of strong pliers, and a hammer; if you've bent up pannier top hooks, you will breeze through this bracket.

The problem is attaching it firmly and permanently to the frame. Dutch bikes come with a brazed or welded socket on the inside of the chainstay to attach this bracket. All I can suggest is some aluminium U-bolts, or that you bend up nylon rod into U-bolts.

DUTCH CITY BIKE PLASTIC CHAINCASES IN USE WITH SHIMANO HUB GEARS
The proprietary (but available to you as spare parts through Dutch bike dealers -- there's a Gazelle dealer in York) Gazelle chaincase clips on and also has a couple of screws to hold it firm. It is both lighweight and silent but not suited to rough use. The first time I crashed (into a tree, avoiding a fat lady who decided to hog the middle of a wide footpath), the sprocket cover popped out and was crunched underfoot. I've used it without since without deleterious effect, though its absence does rather spoil the sleek line. I ran the drivetrain inside this chaincase in 3-in-one light machine oil and it lasted about 3-4 times as long as the open chain on my mountainbike (in the same sort of on-road use, clean and salt-free if sometimes wet).

The much cruder generic chaincase on the Trek weighs more and has no screws: it just clips together. It's not perceptibly more noisy than the Gazelle (or for that matter the Chainglider), perhaps because it is thicker and heavier. Heavier, you should understand, is relative here; a metal chaincase such as the Indian ones, or possibly the Pashey (or metal chaincases available from the same Dutch sources as the plastic ones), would be pounds rather than ounces heavier. Inside this chaincase I used white wax on the chain, and it too gave results 3-4 times better than the open chain on the mountain bike.

However, in both cases the best result was in the order of 2000 miles for the chain and the chainwheel and the sprocket... There is absolutely nothing to account for these results not matching what I hear other people brag about.

(Part 2, below, describes the Utopia Country chaincase, and concludes with recommendations of various chaincases for different cyclists.)

Hobbes

[Andre Jute]

A FULLY ENCLOSED CHAINCASE THAT WORKS
Part 2

(Part 1, in this above, outlines the types of chaincases available, and describes the Hebie Chainglider and several types of Dutch plastic chaincases. Part 2 continues with the Utopia Country chaincase and the conclusions.)

UTOPIA'S COUNTRY CHAINCASE
The Utopia Country chaincase is on a different planet to any of the rest. For a start, Utopia, who care nothing for price if it compromises their unbending standards, designed it to be the best. Not the best in class. Just the best, period. It consequently costs about four times as much as the expensive Hebie Chainglider.

Utopia's Country has 38 or 68 or a 168 parts, depending on which promotional leaflet you read. It isn't intended to be fitted or serviced by anyone except a trained dealer. Nonetheless, Utopia will sell all-comers a Country, and ditto spare parts. You will need the spare parts because to keep the weight down and, in particular, to keep the thing dead quiet, Utopia have designed it with consumable parts. According to the manual, the Country requires partial rebuilding every 2-4 years, depending on mileage.

The Country is different from every other enclosing chaincase on the market. Conceptually it consists of an enclosure for the chainwheel with holes only on each side for the pedal axle, an enclosure for the sprocket with holes to each side for the axle and the axle nut, and two plastic pipes which carry the chain between these enclosures. The devil is in the details. I'll come to how it is actually mounted, which is the important consideration for the Rohloff-equipped Thorn owners.

Utopia's Country is assembled on a lightweight metal framework. Where the pieces fit together, to stop them rattling, they are joined with automobile rubber rivets and a variety of grommets. The only access for the owner is a very small hatch held in with one hex socket head screw and plastic clips; it slides on part of the metal frame and is a pleasure to operate once you have practiced a little. Through this hatch you can oil the chain and by split-link remove the chain from the sprocket in order to drop the wheel. Utopia doesn't offer instructions for fitting a new chain to the Country, or for taking it apart and rebuilding. I repeat, such tasks are intended to be left to the dealer. (Utopia give a ten year guarantee on their frames, which depends on an annual inspection, so the dealer sees the bike once a year and at that time can do what requires to be done, if anything, on the Country.)

Now for the bracketry of Utopia's Country. At the front there is a sort of metal spider inside the Country, to which the plastic backplate is held with screws. This spider fits around the pedal axle and is held firm against the frame by the bottom bracket cup; you thus need a bottom bracket capable of handling a chaincase. There are also hints in the Utopia literature that their Country is designed specifically to work with Kinex bottom brackets, but Kinex are available everywhere and are of excellent quality. At the back there is the familiar socket inside the chainstay, to which a bracket is bolted and onto this bracket is in turn bolted the metal frame of the sprocket cover. I'm sure that Utopia will supply the bracket (they are accustomed to supplying custom fittings to adapt components to their bikes), so all you have to do is work out how to attach the bracket firmly and permanently to the chainstay of your bike.

The rest of the Utopia Country in essence floats in thin air, held up by the chain. There are two tubes, described by Utopia (in German, they have no English literature whatsoever) as of "PE"; Utopia makes a highly-regarded reclining (rather than recumbent) bike with a long chainline, and they've brought over these pipes from successful practice on the recliner. These are not just any old tube you can cut to length yourself. They are flared at the ends to retain the joining pieces (see below) and the material is apparently selected for longevity even with the chain rubbing it constantly. Over the flares fit four tiny, soft bellows. The four bellows are tied to the front and rear roundels and to the PE pipes by eight common tiewraps.

UTOPIA'S COUNTRY CHAINCASE IN USE
Silent, utterly silent. Also very resilient. The Utopia looks spidery next to the Dutch chaincases, even next to the Hebie Chainglider. But in use it is as tough as old boots. It makes the Dutch chaincases, to whose little noise one gets used, sound like diesels on their last legs, and once you ride a Country you understand the people who say the Hebie is noisy.

There's a price, of course, for light weight, full enclosure, sturdiness and silence, all at once. Colin Chapman of Lotus used to say, "Reliability, light weight, low cost, choose only two." The Utopia Country is expensive, half the price of a whole bike for less plutocratic consumers. And, like a Rolls, the Country chaincase must be maintained, rebuilt every two to four years. Certainly at least the exposed thin, soft bellows must be replaced. There are four of them at EUR5 each, plus postage from Germany. The rubber rivets are also offered in Utopia's spares list (22c each), so they too may be consumables.

Utopia, the leader among Germany's baukasten (custom bike builders), was the first manufacturer to specify Herr Rohloff's brand new hub. So it is not at all surprising that you can order their Country chaincase to fit three of the four Rohloff gearing combinations they offer. I think what that works out to is that the chainwheel can have 38 or 44 teeth, and the sprocket can have 16 or 17 teeth, as long as you stay within the Rohloff gearing guidelines in which the 38x16 gearing ratio must not be transgressed. My Country chaincase is the 38x16.

The bike on which I have the Country chaincase has about 1250 miles on it. Through the hatch the chain and sprocket, with the manufacturer's grease on the chain plus a few drops of Oil of Rohloff at 500km intervals, looks new. I clearly don't have enough miles on the combination to make a comparison of wear; it looks like we'll exceed the 2000 mile mark at which my other chaincases give up the drivetrain, but by how much is another story.

WHICH CHAINCASE DO I RECOMMEND?
Depends what you do with your bike and where, and how much you are willing to pay for refinement.

Let's start with hard cases. If you're a downhill racer or a mudplugger, or ride anywhere tree trunks might reach out and snag your bike, only the Hebie Chainglider will be cost-effective. Surprisingly, I think the Utopia Country, being more flexible, may survive abuse as well or possibly better than the Chainglider, but sooner or later you will trash it, and then it is four times the absolute amount of money that will get you a new Chainglider.

If you're a world tourer, those plastic Dutch city bike cases will be smashed before you're out of the Balkans; they are only clipped together. A Chainglider might make it, and would be preferable to the Country for the moment, sure to arrive and more than once, when you're trying to change a chain in a monsoon; just too much on the Country to disassemble, and too fiddly. The Country is definitely one to service on a workstand in a comfortable, warm room, with a mug of tea already coming.

I think nothing of riding on farm lanes and across pastures and ploughed fields with the Country or any of the other types of full chaincases. At this point it becomes a matter of personal choice and budget -- and skill, if only to a tiny extent.

The Hebie Chainglider, if you can get one to suit your choice of chainwheel and sprocket and the length of your chainstays, is a no-brainer to fit.

So, if you're smart cyclist (I'm not, but I cycle in whatever clothes I happen to be wearing, normally khakis), one of the Dutch plastic chaincases can be fitted with a little work, and very likely is the cheapest option here. As a bonus you can with a little searching get the colour you want. I have a two-tone blue one on my blue and silver bike, and one in silver, smoke and black on a black, silver and gold bike. By contrast, the Country and the Chainglider come only in black or silver (and that depends on what is in stock unless you want to face a long wait). Besides, these Dutch plastic cases are in common plastics that can be painted, something that is not at all guaranteed with the Country and the Chainglider. The Dutch plastic chaincases have zero maintenance cost if you don't somehow smash them.

If you want the most refined chaincase, and you don't mind the initial outlay and the routine maintenance every few years, the Utopia Country chaincase is simply the best.

WHICH WOULD I BUY AGAIN?
If I had to consider the cost, and it would fit (it won't fit my custom bikes) I would buy Hebie's Chainglider. I would reject the Dutch plastic chaincases, the Gazelle because it is flimsy despite having screws, the one on the Trek because it is just too obviously generic and crude.

If I commuted (I don't, I work in my study at home), I'd choose the Hebie Chainglider for its sturdiness.

Hobbes

[julk]

Hobbes,
Many thanks for the part 1 and part 2 disclosures on chaincases, much appreciated.

I would hope that Thorn pickup on the most expensive Utopia one and start to offer it. After all if you are buying a Raven bike then greater expense, but lower maintenance, can be viewed as spread over several years.
Julian.

[geocycle]

Hobbes that is a great contribution.  All I have ever wanted to know about chain cases!  I've not seen the Utopia before but a quick google show's it looks good:

http://www.utopia-fahrrad.de/Zubehoer_Html/Kapitel_Html/141_Country_Nachruesten_17.html

It would certainly be worth considering on a new bike or when replacing the drive chain. 

but maybe we should all be using belt drive systems anyway.....!

[stutho]

Thanks for the post, excellent information here!  - N.B.  I have merged the 2 topics

Regards

Stutho

[Andre Jute]

N.B.  I have merged the 2 topics

Thanks. I got a message that I couldn't post more than 20K characters so I split the article in two. If I'd known you can countermand the software, I would have talked to you first.

Hobbes

[avdave]

Belt drive?

Seems good enough to break the round the world record. I'm sure it's a much better solution than a fully enclosed chain. I'd be interested to know whether Thorn have considered the option.

[Andre Jute]

I've made a new thread for "Belt Drive with Rohloff".

[Andre Jute]

Experience with belt drive moved to "Belt Drive with Rohloff".

[Andre Jute]

Here's another fully enclosed chaincase:
http://hubstripping.wordpress.com/2007/12/05/maintenance-free-drivetrain/
This one requires a different drive system on the Rohloff box. Interesting but I'm wary of being the guinea pig of single supplier innovations; the question must be how easily the modification is reversible. However, notice two things: It is truly fully enclosed, and it has a built-in tensioner so, in theory at least, it can work with bikes with suspended rears. It also looks sturdy enough to survive offroading. If so, it'll be the first of its type and deserves to succeed.

Hobbes

[Andre Jute]

I shall have to eat a bit of humble pie here.

Despite my forecast that the Utopia Country chaincase might last a few years, mine has terminated itself in only 16 months. As reported before, small pieces fell off and out of it when the inspection port was opened to oil the chain, and after I made that report, my wife mentioned further pieces she found on the living room patio after I worked on the bike there. Oh dear. Then I had occasion to turn the bike upside down to fit mudflaps to the SKS P65 mudguards and noticed that the Country chaincase had broken around the screws holding the two parts of the front roundel together, and there was a crack an inch and a half long I hadn't noticed before.

It is difficult not to conclude that the Country is built too light for its own good. It is an elegant idea but the construction fights the whole ideal of the bike to which it is fitted, my Utopia Kranich, which is sold as a nearly maintenance-free bike.

As I reported here before, I wrote to Utopia asking how I should pay them for spare parts for the Country when I was merely laying in parts against the day it would have to be routinely rebuilt -- and received no reply. I couldn't be bothered to write again to say the thing had broken and how much for replacement parts; parts are likely to be too much for a chaincase in which I have lost faith. For about 150 Euro, plus postage, if you can even get one, a chaincase should last a bit longer in my undemanding use than 16 months!

I replaced the Country with a Hebie Chainglider. That's another thing about which I must eat humble pie. When I started this thread, what I reported was true: it was impossible to get any Chainglider for the Rohloff but the standard 42-44x17 type, and most of the time you had to take the colour the dealer had. I ascribed this to Hebie's very restrictive marketing policy, specifically their minimum order practice. Now Hebie has seen the light and modularized their Chainglider. You can now buy the front and rear parts separately, and the extra-long front part is actually available at retail to suit longer rear triangles or just bigger bikes, so that you can make up a Chainglider to requirement. In Germany you can buy the parts separately from several dealers or from Ebay but I bought my Chainglider from a dealer who makes up what you require (as long as you'll take black!) from the various spare part options you select on a drop-down menu so that the onus of discovering which parts are required no longer falls on the customer. With all the options, including the extra long front section, it cost 38 Euro and postage was another 15, which is only a little more than you would pay for a Dutch enclosed plastic chaincase (which would still require additional custom frameside brackets, and possibly a new bottom bracket). This more versatile Chainglider doesn't come packaged like the retail kit because it is, literally, made up by the dealer from OEM spare parts; no instructions.

So now you can have a Chainglider for 38, 42 and 44 tooth chainwheels and you can match any of those to a rear section that will take any of the Rohloff sprockets with 15, 16 or 17 teeth. Centre to centre distance can, according to the literature, be up to 530mm with the optional extra long front sections available in all three tooth counts. You can saw the (optional) extra long front section to size with a fine-toothed hacksaw. I sawed about an inch off my extra-long version; the normal length as sold in the standard retail version won't fit my bike at all.

On my everyday ride on a quiet country lane, Hebie's Chainglider is marginally more noisy than Utopia's Country chaincase -- I think; there really isn't much in it. In theory, just looking at how the chain runs in each one, it is (theoretically) possible that one or the other might have more drag. In practice it is much of a muchness; I notice zero difference in efficiency.

The Hebie Chainglider I had on loan several years ago had trouble holding together at the front, where there is a reversal of the clipping direction (I don't know what it is for -- it seems an unnecessary complication). The current model is supplied with a clip to ensure it stays together.

There is a small drainhole on the underside of the Chainglider which I view with the same suspicion as I viewed the vertical split of the Country, as a possible future cause of dirty ankles. In practice the Country never dirtied my trousers, and I suspect the Chainglider's drainhole will soon plug itself. We'll see.

Though I didn't weigh the parts (I'm not a weight weenie!), it seems to me that the Utopia Country, including its beautifully finished metal parts, is lighter than the Hebie Chainglider. The Chainglider is altogether more sturdily made.

I'll report on the Chainglider in use as and when there is something to say. Hope springs eternal.

***

There is also a new contender, called a Chainrunner, which is an articulated plastic tube, split along one side, which fits over the chain and moves with it. It is fitted by Dahon to some of its models and available on Ebay from its German inventor. An experienced cyclist and engineer in Germany tested the Chainrunner and his photographs show that the thing leaks badly, grunge all over the outside, after about the mileage I do on any of my bikes in a year, which some of the commuters who contribute here would do in a quarter. That doesn't seem very practical or economical to me, especially not at 40% of the landed cost of a Chainglider, so I'm not planning on trying the Chainrunner unless and until the price falls to under a tenner delivered.

Andre Jute
Experience is the best teacher

[RobertL]

Have ordered a chainrunner from Taiwan (23 GBP, half being fedex) as my chainring is 39t and therefore falls between the chainglider sizes? Had spotted Danneaux's less than glowing report on these clip on chainguards, but will report back if it performs better than predicted - alternatively would a 38t chainglider fit a 39t chainring?

[Andre Jute]

Have ordered a chainrunner from Taiwan (23 GBP, half being fedex) as my chainring is 39t and therefore falls between the chainglider sizes? Had spotted Danneaux's less than glowing report on these clip on chainguards, but will report back if it performs better than predicted - alternatively would a 38t chainglider fit a 39t chainring?

Look forward to your report on the Chainrunner, Robert. I doubt that the Chaingilder 38T will take 39T without unfortunate side effects. -- Andre Jute

[RobertL]

Unfortunately the GBP23 spent on a chainrunner would have been better spent on a gift to charity - Danneaux's a priori thoughts were right please avoid. Basically it rubs against the rear rim hub and peels off, despite looking neat and well applied. At some point may need to adjust my chainring to one compatible to a Chainglider, or look after the chain with regular tlc. In any event the bicycle trouser clip technology remains proven!

[Danneaux]

Hi Robert!

I think you may be thinking of Frank Revelo's experience fitting the 38T Chainglider to his 36T chainring, as I have yet to try one. I am still trying to get the final definitive word on its viability from Hebie's representative. At first I was told a 38T Chainglider would definitively work with a 36T...then in a subsequent email I was told it must match the same-size chainring for which it is sized.

I am still investigating (another email to them is open in a second window as I write this), and will report back on what they tell me next. I am receiving a number of inquiries from Forum members about Chiangliders as a result of my interest in fitting one to my 36T 'ring, but so far, nothing definitive from Hebie to report.

At the moment, my back-and-forth correspondence allows me to report the following with some confidence:

1) The current run of Chaingliders will work safely with a Rohloff rear hub *if* the Rohloff-compatible rear section is used. It has a larger opening to clear the hub. Earlier versions had an opening that was too small, and resulted in abrasive damage to the hub shell.

2) Most Chaingliders sold use the "Standard" model front section. Despite it being labeled "standard", it can indeed be too short for some Thorns, such as my size 590M Nomad Mk2 (Chainstay lengths vary even between sizes of a given model Thorn). Being able to push the front and rear halves of a Chainglider together so they fasten does not necessarily mean they are the "right" size, and can result in a too-snug fit so the Chainglider doesn't "glide" over the chain.

Hebie advise I would need the "Extra Long" front half...something that is either not widely stocked or widely on offer among vendors. I have found three online vendors so far that carry it, but only one vendor advertises they do. StarBike will make one up out of open stock, but the buyer has to know to specify what they want in the "Comments" section of their online order form -- Christian at StarBike has been a customer-service "star" in answering my availability questions. Hebie also advise the Extra Long front half will need to be cut-down in length, since it will be "too long" for my use as it arrives. To make clear: Hebie tell me my 590M Nomad has chainstays too long for a standard Chainglider, and requires a cut-down Extra Long to fit properly. One must keep in mind the placement of the eccentric bottom bracket when measuring and fitting, as this changes the effective chainstay length, depending on where the EBB is adjusted to.

3) The Chainglider just won't work with Thorn's aluminum chainrings. Those 'rings are too thick below the teeth and will rub on either side of the Chainglider and result in excessive operating friction and -- sadly -- will scuff the finish on the chainring. The one 'ring that appears to universally fit with no problems is the Surly stainless-steel chainring.

4) The Chainglider has been improved starting with the 2010 production run. It is now called the Chainglider 3.0. The difference is the 3.0 does not have the center clip at the forward part of the Chainring. Some online stores still have old stock...or simply haven't updated their photos. The 3.0 version is supposed to be easier to fit as the front case half snaps together as it does elsewhere.

All the above explains in part the wide variation in successful use by customers.

It has taken awhile to get and confirm the above information, and still leaves the most important bit yet unanswered: How much variation in tooth size will the front case half accommodate? Will the Chainglider *only* fit the recommended tooth size for which it is made, or will it *adequately* fit and cover variations, and if so, how acceptably and how much variation? Frank's outcome would not be a good one for me, as it left most of the rear portion of the chainring is exposed to the elements. I have asked Hebie if this is a "typical" outcome when a 36T ring is matched to a 38T 'Glider or if it is a result of using a Standard front case-half where an Extra-Long is indicated. I'm going to ask again, as this is key to whether or not it will work for myself and others.

Robert, I'm so sorry you've had such bad luck with your Chainglider. I really appreciate your thoughtfulness in reporting the results of experience.

All the best,

Dan