Author Topic: Chain glider advice  (Read 14894 times)

JohnR

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Re: Chain glider advice
« Reply #30 on: April 10, 2021, 08:52:02 AM »
EDIT: I see the surly chainring is 110mm, does that mean the bottom bracket has to be 110mm ?
No. The bottom bracket number is (I think) the axle length whereas the chainring is interested in the diameter of the circle for the bolts fixing the chainring to the cranks. Thorn use a square taper bottom bracket. This type means the crank axle has slightly tapered square ends onto which the cranks are fixed by nuts. Different square taper cranks would fit 110 (or 130) BCD / PCD cranks. There's a place called SourceBMX which sells 104BCD steel chainrings. I'm using one of those so I could fit a chainglider on my Mercury which has the same 104BCD cranks.

Yes, the Tange Seiki BB is compatible with the Shimano UN55. Only time will reveal if it is of the same quality.

It may be worthwhile watching Thorn's listing of ready-made bikes in case something suitable appears. They probably have some bikes as demonstrators on the basis that business should soon return to normal and people can visit the shop and try different bikes.

Andre Jute

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Re: Chain glider advice
« Reply #31 on: April 10, 2021, 05:08:31 PM »
I've put a short article in the Rohloff forum to relate all the components in the transmission of the bike near the bottom bracket together spatially, because it causes novices, and some old hands too, considerable confusion:
Specifying the BB axle length WRT the Rohloff HGB chainline

ourclarioncall

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Re: Chain glider advice
« Reply #32 on: April 12, 2021, 06:11:59 PM »
I from heard from Thorn today that they have no 26” forks left for nomad mk3 builds until March 2022 !!

 so looks like my only choice is a mk2 in 620M or 620L

I do “just” fit into the height measurement for this frame which Thorn says is the equivalent of a 21” mountain bike frame.

So hmmm 🤔 need to ponder this one

What is your time frame?
Less than a year to wait.
I love a good countdown.
More time to save up for extra goodies. And there will be lots.
The anticipation. Expectation. Marking those weeks and months off on the calendar.

Don't compromise. Get it right first time.

Impatient me wants it now now now haha. But patient me can usually wrestle him down into subjection.

I need to figure out exactly what frame size I need and can’t find my tape measure which is no surprise in this chaotic house. I did measure myself before a while back but can’t remember exactly.

I know I can fit into 565L,  590L, and 620L

Speaking to a couple guys on YouTube , one is 6 foot and has the 565L and says the 590 is massive for him. Another guy who is just over 6 foot 1 inch has the 620L and didn’t like a smaller size. He DOES use butterfly bars tho which may have an effect on things.

So yeah, it’s quite fascinating how guys of similar height can vary so much. I guess there’s other factors than just height such as limb length.

I read in old thorn literature that the 620L is a rough equivalent of a 21” mountain bike frame , so that’s language I can relate to and understand. 590L = 19” frame, 565L = 17” frame.

I also have a 13 year old (sit at computer all day) who is about 6 foot and close to 16 stone and he is still growing , so just now he is about the same size as me but could be 6’ 6” by the time he has stopped growing and a 620L would be a fine fit for him then.

If I went for a 620L is could be a safe risk as I know my son could get the good of it and would love to get him into touring

There’s also a mk3 nomad size 580L that I’m sure would be a good fit for me but it’s derailleur. Not exactly what I want but possibly I could get it rohloffed

It seemed like most of the other nomad mk3 frames are sold out, well in my size anyway.

I could also buy second hand which I’m willing to do but it’s rare that the right bike comes up. Saying that, there has been quite a flood of thorn bikes on eBay recently so better time of year for buying

Probably best thing to do is find or buy a new measuring tape, get my measurements done accurately and get advice from Thorn

ourclarioncall

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Re: Chain glider advice
« Reply #33 on: April 12, 2021, 06:17:49 PM »
I've put a short article in the Rohloff forum to relate all the components in the transmission of the bike near the bottom bracket together spatially, because it causes novices, and some old hands too, considerable confusion:
Specifying the BB axle length WRT the Rohloff HGB chainline

Good stuff Andre 👍 yeah it can bamboozle the old brain a bit. Can’t believe I d been riding bikes my whole life and only now have taken the time to try and understand how they work . Bikes are such an amazing invention!!

ourclarioncall

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Re: Chain glider advice
« Reply #34 on: April 12, 2021, 06:18:59 PM »
JohnR

Cheers again John, I think I get it all now , makes sense . Appreciate your patience with my conveyor belt of questions  ;D

beagley

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Re: Chain glider advice
« Reply #35 on: May 21, 2021, 04:43:53 PM »
Sadly, the Chainglider didn't work out for me due to incompatible chainring. Hence, front & rear parts are for sale, in case anyone is interested (hope this is OK with the admins, please remove if not):
https://www.ebay.co.uk/itm/174776547253 Front (38T)
https://www.ebay.co.uk/itm/174776547625 Rohloff 15-17T - Rear
« Last Edit: May 21, 2021, 04:47:02 PM by beagley »
 

JohnR

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Re: Chain glider advice
« Reply #36 on: May 21, 2021, 10:46:30 PM »
Sadly, the Chainglider didn't work out for me due to incompatible chainring.
I bought a chainglider-compatible chainring from https://www.sourcebmx.com/products/jet-bmx-4-bolt-race-chainring.

John Saxby

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Re: Chain glider advice
« Reply #37 on: May 22, 2021, 02:05:47 PM »
I've bought 'glider-compatible chainrings from Rivendell Bike Works, here:
https://www.rivbike.com/collections/cranks-bbs

Mine is the 36T x 110--I bought two a year-plus ago, as future-proofing--but of course the 38T would fit as well.

These are lovely alloy items, made for RBW by Origin8.  The toothed portion is 3 mm exactly, so fits the 'glider. I did an additional bit of cosmetic surgery on my 'glider to reduce any possible friction further still, details on request.

Matt2matt2002

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Re: Chain glider advice
« Reply #38 on: May 22, 2021, 06:40:24 PM »
Details please, John.
Never drink and drive. You may hit a bump  and spill your drink

JohnR

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Re: Chain glider advice
« Reply #39 on: May 22, 2021, 06:56:53 PM »

John Saxby

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Re: Chain glider advice
« Reply #40 on: May 22, 2021, 09:38:57 PM »
Cosmetic surgery on my 'glider, Matt:

(I realize that this is desecration for some, but in mitigation, yer honner, I did it only 'cos Hebie doesn't make a 'glider designed for a 36T ring.)

Two bits:

First, to accommodate my switch to a 36T ring:  (you don't need this, I think -- your ring is a 38T item, no?)  I cut out the rear portion of the front circular section, the part encasing the rear part of the chain ring.  Makes no noticeable difference that I can see in dirt'n'crud finding its way into the 'glider.  As a precaution, I wrap a couple of turns of plastic electrical tape around the upper and lower runs of the 'glider, close to the ring itself.

Second, for the 36T Rivendell alloy ring, 3 MM:  (The Surly 36T steel ring is slightly thinner, so doesn't need this extra attention.   OTOH, the Rivendell ring gives me a chain with no tight spot, first time I've seen that in a lifetime of riding chain-driven two-wheelers.)  So:  on the inner faces of each of the two clamshell halves of the front portion of the 'glider where it encases the front part of the chainring and the chain itself, there's a small collar, about 2 - 3 mm high.  As the 'glider encases the front portion of my Rivendell ring, that collar sits just over the toothed portion, and close to but not touching the thicker part of the chain ring below the teeth.

I used a sharp knife to remove the collar on each side, just to ensure that neither the teeth of the ring nor the portion just below the teeth rub on the 'glider.

Again, no noticeable entry of crud.

(But there is a noticeable weight loss on steep hills. ;) )

Hope this helps, Matt.  I could take a picture if my words don't suit -- don't hesitate to let me know.

Cheers,  J.
« Last Edit: May 22, 2021, 09:40:58 PM by John Saxby »

Matt2matt2002

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Re: Chain glider advice
« Reply #41 on: May 23, 2021, 10:01:31 AM »
Thanks John.
All clear now. Alles ist klar.
Nice tip re the electrical tape.
Good memory, I do indeed run a 38 front ring. Surly ,thin.
I recently purchased a replacement although I haven't flipped yet. I don't have the figures in front of me for its milage.
I guess these things are eye balled for renewal?
Milage/ conditions etc must be wear factors?
I've not heard of a measurement guage.

18 months after buying the Raven, second hand in Feb 2013 ( but with few miles on the clock ) I embarked on my self supported north to south end 2 end of Scotland trip.
I took the ferry from Aberdeen to Shetland and visited Muckle Flugger, the furthest point North in the British isles.
On my way back to my accommodation on Yell the chain began skipping the front ring. In fact I could not peddle at all. No grip whatsoever.
I had to push/ walk for 12+ miles.

Long story short; the 1 bike shop in Lerwick searched through a junk box out back and found a compatible replacement.
I was thinking I'd have to ferry home to Aberdeen but he saved my bacon.
This was pre Chainglider days so no comparability issues but was lucky he had one to fit my crank/ BB.

I managed to continue my tour South to the Mull of Galloway.
I wish I'd taken a picture of the worn ring but I recall the mechanic mentioning sharks teeth!





Never drink and drive. You may hit a bump  and spill your drink