What's your Rohloff combo (chainring, cog)?

[il padrone]

Not at all!Correct, by all my calculations as well.It's not you, Jim, but I think your/our analysis fails to take into account the healthy safety margin Rohloff engineers into their hubs. (others will hasten to correct -- as they should -- if my assumption is incorrect).

From Thorn's "Living with a Rohloff" document:

Rohloff will not give a warranty on the hubs, when a gear, with an input ratio smaller than 40 x 17 is used on a solo bike (42 x 17 on a tandem). However Rohloff say that even “world class athletes” are warranted to use such a gear.

So if you are riding with Lance, Cadel or Bradley, be very strict about the 'red gears'. Otherwise, for us mere mortals I don't think it is a huge issue. Also note - I do believe the torque limit is independent of wheel size. The same gear in a 20" or in a 700C wheel generates the same torque - it's simply that the load and/or the speed will differ.

[Danneaux]

...torque limit is independent of wheel size...

Yep. Andre set me straght on that one. And, it makes sense when you stop to think about it. It is the ratios, rather than the moment arm of the wheel size that determine torque levels internal to the hub.

Best,

Dan.

[JimK]

I do believe the torque limit is independent of wheel size.

Ah, thanks for that, showing that Rohloff indeed wants a higher ratio on a tandem, though nothing like double the solo.

Suppose Rohloff did insist on a 80 tooth chainring for a tandem, twice the 40 tooth solo ring. It'd be the devil to get a tandem up a big hill with that! Unless you drop the wheel size down to say 13 inches at the same time! That would bring the overall gear ratio down to what the solo gear was, without, as you say, affecting the torque at the sprocket.

In a week there'll be a race right here:
http://www.tourofthecatskills.com/

The teenager and I plan to ride over to the route with a camera. I hear some of the racers will walk on sections up that big hill. I've ridden it but had to stop a few times to catch my breath. I don't know if we'll be able to get up along there during the race - how much of the road do they block off? That road is not just steep but narrow and sort of half falling off down the cliff...



These are the hills that make me think about lower gears!

[martinf]

I hope Hebie knows where to send the cheque!

I used to be in advertising and my erstwhile associates will turn in their graves to hear that I give such good word of mouth free of charge...

Andre Jute

Chainglider arrived yesterday, it was easy and quick to fit. But I took it off straight away as the chainring seemed to rub when I turned the cranks by hand.

The instructions say chainrings < 3 mm. Mine is a tad wider than that, its a TA Cyclotouriste for 1/8" chain, and the Sedis 1/8" chain is I reckon just under the max recommended of 9 mm.

I measured some other chainrings for 3/32" chain on other bikes (all TA of various sorts), they were no narrower, all a tad over 3 mm, so I thought about the apparent stiffness of a SON hub when you turn it by hand, put the chainglider back on and did a 25 km ride to try it out.

Not completely silent, there was a sort of swishing noise that I think came from the chainring rubbing on the edges of the chainglider, and a very slight grating noise that I think is the chain rubbing somewhere inside. Neither noise is particularly loud, and I think the swishing noise reduced somewhat by the end of the ride. The grating is pretty faint, about on a par with the noise from the tensioner pulley on my bike with the Nexus 8 premium hub.

I reckon there would be less noise with a thinner chainring (steel ?) and a 3/32" chain.

[Danneaux]

Hi Martin!

I'm very much looking forward to your extended user reports on the Hebie Chainglider. Already, what you have reported is a vast help.

Robin advised me the chainglider needs a thinner ring, and gave an example:

http://www.sjscycles.co.uk/surly-110-pcd-5-arm-stainless-steel-chainring-38t-silver-prod20828/

I realize the Surly is not compatible with the T/A pattern, 50.4mm* BCD crank you're running, but something to keep in mind. It would be helpful to know exactly how wide/thick the Surly 'ring is for comparision. No doubt Andre can enlighten us on both points, based on his own lengthy experience.

Martin...can you please keep a close eye out for any possible rubbing and abrasion between the right side of the Rohloff hub (just inboard of the cog) and the opening in the Chainglider? This is where I would expect problems to arise...if any. [EDIT: Oops. I realize you're not running it with a Rohloff. Still, all the other information is helpful]

Meanwhile, I have decided to go with a pie-plate/bashguard style chainring cover so I will have no concerns about trapping dust inside while desert touring. Still bvery much looking forward to how these work for others, and also looking forward to your next installment. The photo was an ideal complement to your written report; well done!

Best,

Dan.

*Edit from my original statement, wrt "49BCD". My mind was thinking "Stroonglight 49D" which shared a base crankarm spider dimension with the orginal T/A Cyclotouriste, and somewhere along the way, that thought came out the fingers wrong...happens)

[Andre Jute]

... chainring seemed to rub when I turned the cranks by hand...

Not completely silent, there was a sort of swishing noise that I think came from the chainring rubbing on the edges of the chainglider, and a very slight grating noise that I think is the chain rubbing somewhere inside. Neither noise is particularly loud, and I think the swishing noise reduced somewhat by the end of the ride.

Super photograph, Martin.

The noise, and especially the grating, tells us there is something amiss in your installation. I'd check the inside of the Chainglider every 25 miles to see if the teeth or the chain sides are marking the plastic. The thing's so hard, you'll probably not see a mark before then.

I use a KMC X8 chain and a Surly stainless steel chainring with a standard Rohloff 16t sprocket inside my Chainglider, and for practical purposes it is silent. My test is to ride on the white or yellow line on a smooth tar macadam road; the paint removes my fat tyres from the equation. My bike is dead silent -- the electric motor is the loudest thing about it, surprisingly, and then the tyres on anything but dead smooth roads -- so I would hear instantly if my Chainglider grated.

There's a trick to fitting the Chainglider. If there's any kind of a contact noise, I move only one side, top or bottom, of the long tubes one notch in or out of the sprocket cover. The noise will lessen or increase. If it lessens, I try another notch, if it increases I try a notch the other way. If still no improvement, I try the other tube. It's probably a year since I last adjusted my Chainglider, at the time I fitted a Cospea crank and the Surly chainring.

What this adjustment does is a sort of magic. Clearly, the Chainglider must touch the chain somewhere, and I suspect it is at the chainring and sprocket, leaving the run of the chain between, where it would be noisiest because slack, to run just clear of the hard rubbery substance of the Chainglider. The adjustment seems to balance the two long tubes on the sprocket, so to speak, at the point of least interference. On my installation, it seems, magically, to be a point of no interference because there is no noise.

Robin advised me the chainglider needs a thinner ring, and gave an example:

http://www.sjscycles.co.uk/surly-110-pcd-5-arm-stainless-steel-chainring-38t-silver-prod20828/

I realize the Surly is not compatible with the T/A pattern, 49BCD crank you're running, but something to keep in mind. It would be helpful to know exactly how wide/thick the Surly 'ring is for comparision. No doubt Andre can enlighten us on both points, based on his own lengthy experience.

The 38T Surly stainless steel chainring is 2.6mm +- 0.01 thick by my measurement.

The Surly Robin recommends and that I use is a 110BCD fitment. I don't have enough mileage on mine to be able to tell anything about it, except that its square cut nature doesn't create additional noise. (It's intended for fixies and "single speed" bikes.)

Surly doesn't make a 52mm BCD fitting stainless chainring, so unfortunately you can't use a TA Cycletouriste with the attractive stainless chainring unless you make an adapter. Surly does however make 130mm chainrings, for which an adapter used to be available.

Andre Jute

[martinf]

The noise, and especially the grating, tells us there is something amiss in your installation. I'd check the inside of the Chainglider every 25 miles to see if the teeth or the chain sides are marking the plastic. The thing's so hard, you'll probably not see a mark before then.

There's a trick to fitting the Chainglider. If there's any kind of a contact noise, I move only one side, top or bottom, of the long tubes one notch in or out of the sprocket cover. The noise will lessen or increase. If it lessens, I try another notch, if it increases I try a notch the other way. I still no improvement, I try the other tube.

The 38T Surly stainless steel chainring is 2.6mm +- 0.01 thick by my measurement.

The Surly Robin recommends and that I use is a 110BCD fitment. I don't have enough mileage on mine to be able to tell anything about it, except that its square cut nature doesn't create additional noise. (It's intended for fixies and "single speed" bikes.)

Surly doesn't make a 52mm BCD fitting stainless chainring, so unfortunately you can't use a TA Cycletouriste.

I tried adjusting the notches (very quick to do), and think I have reached the best compromise for the transmission I have. I think the swishing is due to the TA ring being slightly wider than the max. specified by Hebie. For Rohloff use that means the Surly stainless steel ring at 2.6 mm would be a good option.

The grating is not very obtrusive. I can only really hear it when going slowly up fairly steep hills (masked by wind/tyre noise at normal speeds) and reckon it might be the slack lower run of the chain or maybe the ends of the chain pins, these stick out a bit on the old Sedis 1/8" chain I have on the bike, which I measured to be just inside 9 mm. Again, things would would probably improve  for Rohloff use with the eccentric bottom bracket to adjust chain tension and a narrower modern 3/32" chain. Chain tension adjustment on my 5-speed is a bit hit and miss.

So not a perfect fit for the equipment I have on my old 5-speed, but still usable. I now intend trying it out to see if:

1 - there are any performance reductions. For this I timed myself for four 25 km rides over a moderately hilly local route before fitting the chainglider, so I will do the same route 4 times with the chainglider to see if it makes any difference to average speed, bearing in mind that my current installation is not ideal.

2 - any other drawbacks, apart from the weight (not very significant) and the slight extra time needed to remove the rear wheel. As the 5-speed is my utility bike, it should get a fair amount of use before I order my Thorn.

3 - whether it works or not to reduce chain maintenance/increase transmission life. My test for this will be to go and ride a local cycle-track through the sand dunes for about 40 kms, then open the chainglider when I get back home. If its still reasonably clean inside I will consider the case proven.

[Andre Jute]

That sounds like a scientific plan, Martin.

(I can't resist: http://coolmainpress.com/ajwriting/archives/2490 )

For the record, a couple of notes. A Rohloff installation on a new hardtail that requires a chain tensioner to work is simply incompetent (1); it also defeats several purposes of fitting the expensive gearbox, among them low maintenance and long chain life. Also, a Rohloff chain is supposed to be quite slack; a tight chain will wear faster than necessary.

Andre Jute

(1) Of course, a Rohloff installation on a repurposed (old) frame with vertical dropouts simply has to use the chain tensioner unless you can find an eccentric bottom bracket small enough to fit in a normal bottom bracket shell.

[il padrone]

I've just recently converted my wife's bike to Rohloff. It is a very reliable '93 Giant Sedona cromoly MTB, ideal for rough stuff touring and still in excellent condition. But it has vertical drop-outs so I have had to get the Rohloff with a chain tensioner (and torsion arm). So far this is all working quite well. I don't see how the maintenance of the hub will be compromised by this, and the wear on the chain should not be noticeably more than for any other chain. The heaviest wear factor for the chain is going to be the pressure put on the pedals, together with the amount of dirt and grit that gets onto the chain.

Time will tell I guess, but I'm not going to lose sleep over it.

[martinf]

For the record, a couple of notes. A Rohloff installation on a new hardtail that requires a chain tensioner to work is simply incompetent (1); it also defeats several purposes of fitting the expensive gearbox, among them low maintenance and long chain life. Also, a Rohloff chain is supposed to be quite slack; a tight chain will wear faster than necessary.

Andre Jute

(1) Of course, a Rohloff installation on a repurposed (old) frame with vertical dropouts simply has to use the chain tensioner unless you can find an eccentric bottom bracket small enough to fit in a normal bottom bracket shell.

I had to use a tensioner on my testbed for different handlebar positions. This is the old mountain bike I took on my October 2011 tour to Spain and back. In addition to changing the handlebars I took off the deraillur parts and rear U-brake, keeping the largest 44T ring, which I moved to the middle position, and fitted a Nexus Premium 8-speed wheel.

I chose a Surly Singleator, pushing gently upwards to keep the chain on over bumps, but still leaving a bit of slack. I can always increase the tension if the chain comes off. The Singleator seems to add very little drag. But obviously not possible to try out the chainglider on that bike.

I timed five 50 km "before and after" rides around the same circuit in each configuration, flat bars/Nexus was about 3% slower than drop bars/deraillers.

[Andre Jute]

I timed five 50 km "before and after" rides around the same circuit in each configuration, flat bars/Nexus was about 3% slower than drop bars/deraillers.

This is very impressive indeed. I would say at a guess, open to correction of course, that the wider range of the Rohloff means that its efficiency loss might be about 1% that of derailleurs or even "lost in the margin of error". Of course, your impressive numbers depend crucially on using the gearbox well, which isn't the case for all Shimano Nexus riders... I've found that the Rohloff, for one reason and another, encourages a more sporting style of riding, working the box more often, less of a temptation to hang on to high gears.

Just as a matter of interest, I found that when I went to a fully automatic Nexus box ( http://coolmainpress.com/BICYCLINGsmover.html  ) from a manual Nexus box, I went perceptibly faster over the same old familiar daily ride because I wasn't hanging on to unsuitable gears. That Shimano Cyber Nexus setup was a real eye-opener. It left any derailleur system I ever rode for dead.

Andre Jute

[triaesthete]

Hi Martin
500km of testing is thorough. Chapeaux!

Does the singleator feel like a quality item. On One do something similar called a Doofer http://www.on-one.co.uk/i/q/FSOOSSD/on_one_doofer_singlespeed_chain_tensioner

General question: has anyone converted a Thorn Sherpa/Club tour/Audax to Rohloff  by:- A: using one of the above? B: welding extensions to the left rear drop out to modify it to take the oem torque arm?

If not does anyone think B is possible from materials and torque loading standpoints?

Interested
Ian

[rualexander]

I use my Sherpa with a Rohloff hub.
Started with chain tensioner but after a couple of months got rid of it once I found this magic gear calculator which allows you to work out which chainring and sprocket combination will allow you to get a chain to fit without the tesioner. As Andre mentions above the Rohloff is happy with a slack chain so no problem.
For my Sherpa 610S a 38T chainring and 16T sprocket works fine.

I do use the long torque arm, but its no problem, only had the wheel off a couple of times in the past year anyway, it doesn't look great but that doesn't bother me.

There's a thread on my Sherpa here : http://www.thorncycles.co.uk/forums/index.php?topic=3235.0

[martinf]

This is very impressive indeed. I would say at a guess, open to correction of course, that the wider range of the Rohloff means that its efficiency loss might be about 1% that of derailleurs or even "lost in the margin of error". Of course, your impressive numbers depend crucially on using the gearbox well, which isn't the case for all Shimano Nexus riders... I've found that the Rohloff, for one reason and another, encourages a more sporting style of riding, working the box more often, less of a temptation to hang on to high gears.
Andre Jute

For me, with the rather subjective method of timing 2 sets of 5 rides, 3% is already a fairly negligible difference.

Unfortunately, it isn't a straight hub/derailler comparison because I changed the bars at the same time. I would expect flat bars to be slightly slower, due to the absence of brake levers I spend less time on the bar ends than I spend on the hoods with drop bars.

I would imagine that a Rohloff should do slightly better than a Nexus 8 Premium because:

1 - the gear steps of the Rohloff are closer, so slight gain from being in a more optimal ratio.
2 - the Rohloff runs in oil, the Nexus in grease (unless and until I find a low-hassle way of using it with oil).

Another factor is that my Nexus is nearly new and still on the original grease.

I've found that hub gears generally work better after riding for 1,000 kms or so, cleaning out the original grease/oil and relubricating.
  

[martinf]

Does the singleator feel like a quality item. On One do something similar called a Doofer http://www.on-one.co.uk/i/q/FSOOSSD/on_one_doofer_singlespeed_chain_tensioner

The singleator seems good quality, but I haven't used it for long. It came with two different springs, factory fitted for pushing down, and an another one for pushing up. I preferred to try the latter as it gives more chain wrap on the rear sprocket. It will cope with a max. sprocket of 24T, which I have.

From the photo, the singleator has one advantage over the Doofer - the spring is enclosed. Don't know how you adjust the tension on the Doofer, but the singleator is dead easy - loosen the mounting bolt with an Allen key, adjust the flats on the tension adjuster with a cone spanner, tighten the mounting bolt again.