Thorn Cycles Forum
Technical => Wheels, Tyres and Brakes => Topic started by: FrogPrince on May 14, 2015, 03:46:08 pm
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When I Purchased my New Raven about 18 months ago I chose Grizzly rims, standard front and CSS rear. They seemed like a good idea at the time. After a few weeks there was an ominous click when braking and I discovered the rim joint had pulled out of line creating a step. I returned the wheel to the workshop and the rim was replaced. Not many weeks later the click started again. I tried rubbing the join down (difficult on a carbide rim) and the worked for a short time. Frustrated I decided to put up with the noise. Then gradually over a period of time the back wheel started to lock as the valve went through the brake causing some dangerous skids going down hill. On investigation I discovered a longitudinal crack either side of the valve on the inside of the rim under the rim tape, causing the rim to spread at this point! I returned to the workshop again . they agreed to replace the rim with an Andra rim free of charge as the rim had only lasted a year and 5000 miles. I still had to pay £50:00 building fee. The new wheel seems much better. I will add that the standard Grizzly front rim has performed faultlessly. I feel I was ill-advised. Any thoughts????
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50 quid seems steep as they charge 40 for a someone that hasn't already paid once but got sub-par service.
http://www.sjscycles.co.uk/wheel-build-labour-with-14-15g-dt-competition-stainless-silver-spokes-per-wheel-prod5027/
In my opinion they should of not made you paid for the labour.
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I think you may have just been unlucky to have the 2x Grizzly rims crack/ fail. Quite rare I suspect - I've had about 3 pairs in almost daily use for over 6 years without any structural problems.
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I've had two pairs of Grizzly rims on my Nomad and Raven. The Nomad is nearly 3 years old, the Raven is 2 years old. Between them I've done over 8,000 miles - no sign of trouble at all.
I suspect the OP has been unlucky
Fraser
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50 quid seems steep as they charge 40 for a someone that hasn't already paid once but got sub-par service.
http://www.sjscycles.co.uk/wheel-build-labour-with-14-15g-dt-competition-stainless-silver-spokes-per-wheel-prod5027/
In my opinion they should of not made you paid for the labour.
SJSC price for wheel builds depends on the number and type of spokes used, and the type of hub. 50 quid sounds about right for a black (?) Rohloff build.
As for the OP's problem in general, I'd expect to get more than 5,000 miles / 18 months from any rim. Given both failed after a relatively short period, and it didn't result from wear, I guess SJSC should raise it with the manufacturer as this indicates a bad batch. Unless yours was an isolated case, but then I agree they could do a bit better than this and sell you the wheel/rim half-price rather than charging for the more costly element of it.
Don't think I'd expect a new wheel FOC though, after all you got 5,000 miles from the original one...
Happy riding!
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My thoughts were that it was a bad batch. It was interesting when I phoned the guy in the workshop new exactly what the problem was before I said much. Perhaps they had had others from that batch fail??? Wheel build labour was £46:12 ...... I forgot that I bought some brake inserts as well :-)
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Very unlucky, I've got over 16000 miles out of my grizzly rims so far. From what you say, I would have thought you deserved a new wheel FOC and SJS should chase their building costs up with Ryde. I suppose it is a grey area with 5000 on the clock but .....
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Hi Colin!
So sorry to hear of your misfortune, and I hope things will stay sorted from now on.
Please, can you tell us what tire you were using in the rear, and at what inflation pressure?
Can you also tell me if the rim was drilled for presta, or if it was redrilled larger in diameter for a Schraeder valve?
Pressure and valve drilling don't sound like culprits in the rim-joint misalignment, but when I heard about the crack near the valve, it made me wonder if there might be other contributing factors to the failure itself, if the rim happened to be already somewhat marginal.
All the best,
Dan. (...who always likes to autopsy failed components)
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Hi Colin!
So sorry to hear of your misfortune, and I hope things will stay sorted from now on.
Please, can you tell us what tire you were using in the rear, and at what inflation pressure?
I am using schwalbe Dureems (sp?) At 50 psi on the rear.
Can you also tell me if the rim was drilled for presta, or if it was redrilled larger in diameter for a Schraeder valve?
Drilled for presta
Pressure and valve drilling don't sound like culprits in the rim-joint misalignment, but when I heard about the crack near the valve, it made me wonder if there might be other contributing factors to the failure itself, if the rim happened to be already somewhat marginal.
All the best,
Dan. (...who always likes to autopsy failed components)
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Hi Colin!
Thanks!
Looking a Thorn's pressure recommendations on page 35 of the current Mega Brochure ( http://www.sjscycles.com/thornpdf/THORN_MEGA_BROCHURE.pdf ), it looks like tire pressure wasn't a factor and the standard presta drilling wasn't the larger size required for a Schraeder valve.
Looks like the rims themselves were indeed the problem, rather than something else pushing an already marginal example over the edge.
I feel sure the switch to an Andra rim will signal the end of any possible problems. I've now had a lot of experience with Andras in demanding conditions, and they just keep rolling along.
All the best,
Dan.
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Oh dear oh dear! ??? I have recently replaced my Grizzly with a new one after similar symptoms to the OP. Like him I put up with it for quite some time before doing anything about it. Mine was way out of warranty and had done about 10000km. It was fitted to my new Sterling in July 2010.
I do recall a very bad crash into a Spanish pothole sometime previously. I wondered about changing to an Andra but decided it was my fault and so stuck with the Grizzly. I hope I won't be disappointed....
(http://i192.photobucket.com/albums/z29/rafikiphoto/AjhLIbI_vYYoMKd3hTo0hdO6BwE_-JnOYGEYGedhFfv0_zps9ayhejaw.jpg)
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I had a similar problem with the Grizzly rim on the rear wheel on my Sherpa - but that was due to running at too high tyre pressure. I replaced the rim and followed Jim K's advice and reduced my tyre pressures to what he recommended, and we've been OK Thanks Jim.
Interestingly like the OP my front wheel rim has been fine with no issues.
I did e-mail Ryde about the problem - but they never replied.
http://www.thorncycles.co.uk/forums/index.php?topic=8057.0
Pete.
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That does look like a fault waiting to happen with which the rim arrived from the factory. A wheelbuilder would need a steampowered ham hand to get it that badly wrong, and I just don't believe in a pothole that could split a rim lengthways unless there was some manufacturing error already waitig for an impact that a sound rim would shrug off.
And a pretty frightening sight too. I can imagine half your rim and some of your spokes going bush while the rest of your wheel collapses under you in slow motion. All those unterminated spokes behind and below you... Deja vu for every actor who ever played Ceasar.
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I had a similar problem with the Grizzly rim on the rear wheel on my Sherpa
Was it CSS? I wonder if the issue is peculiar to carbide coated rims, or all of them when build up in the rear, i.e. heavier load.
Anyhow, three months ago I was choosing between Sputniks and Grizzlys, and Spa recommended the former. Now glad I took their advice!
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Kuba - Yes it was a CSS.
Pete.
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I would have expected a story like this to involve rim wear on a non-CSS rim. For example one of my neighbors had a rim split, but he commutes on his bike and had worn down the rim braking surface. (That is in part why I bought the CSS.)
I can't imagine that the CSS would have caused this type of failure, a split in the middle is far from where the carbide was added to it.
A friend of mind did a cross country (USA) trip that I think was about 4,000 miles (~6,000 km). He said that everybody in the group had to replace a rear wheel. I think that was excessive too, they were all carrying camping gear on their bikes but still that is not that much weight. There are some overweight people that put that much weight on a bike wheel without any camping gear on the bike. He said that they dipped their wheels in the Atlantic at the start and in the Pacific at the end. I wonder if they might have gotten some corrosion from the salt water in the rims? I have no clue if this is a valid concern, but a common factor in this case is that they all started the trip with a salt water bath in their rims. Was there any sign of corrosion inside the split Grizzly rims?
If you replace the rim with the same brand and model of rim and if you reuse your spokes, you can:
- loosen all spokes but keep the spoke nipples threaded onto each spoke,
- tape the new rim next to the old one putting the valve holes together,
- move one spoke at a time from the old rim to the new (obviously do this with the easiest ones first),
- when completed, true it up, prestress it and check final tension.
This is a lot less labor than a new build with new spokes. If you know how to true a wheel but not how to lace up a new wheel, you at least can transfer the spokes from an old to new rim this way.
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I have had a very similar problem with my 32 hole CSS 26" rear rim. I had the problem that the rear v-brake was grabbing the rear wheel and causing the wheel to lock and skid. After a fruitless hour of trying to true the wheel I realised that at particular point that there was a high point on both sides. I measured the rim width and yes it was 2mm wider at one point, about the breadth of one spoke spacing. Affter reading this is took the tire off to see that there is a crack between 3 poke holes. Not great picture but shows the crack. I bought the rim secondhand with 500 miles on it, and have ridden another 4500 miles, in 18 months. Very disappointed this has failed. I would not have exceeded the Schwalbe max. psi for 1.75" Marathon plus or for 2" kojaks. I weigh about 90kg, but this was used for commuting. Just thought I would register my annoyance, and share this might not be that rare. Thanks.
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I would not have exceeded the Schwalbe max. psi for 1.75" Marathon plus or for 2" kojaks.
Hi Tim!
It appears more and more as though the manufacturers' inflation ratings are just too much for good rim life -- especially when narrow(er) rims are combined with wide(r) tires.
I'm sure sorry yours failed. Perhaps the original owner unknowingly ran too-high pressures?
Best,
Dan.
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I would not have exceeded the Schwalbe max. psi for 1.75" Marathon plus or for 2" kojaks.
For the wider tyres, I consider the Schwalbe maximum pressures as being too high.
I now take care not to exceed Thorn's recommended pressures, which are lower. These are listed on page 31 of their mega-brochure, version 1.01.
Thorn also list absolute pressures. If necessary, I will sometimes pump to Thorn's maximum absolute pressure to help with seating a tyre properly, but I then deflate to Thorn's recommended maximum or less.
I believe the purpose of Thorn's absolute minimum pressures are to avoid "snakebite" punctures and carcass failure due to excessive flexing. I respect these minimum pressures on my own bikes, but I use lower pressures on my wife's bike, which is very lightly loaded and not used aggressively on rough surfaces.
So long as the pressure falls within the Thorn recommended limits, I try and get close to the 15% tyre drop recommended by Jan Heine in his March 2009 article in Adventure Cyclist.
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So long as the pressure falls within the Thorn recommended limits, I try and get close to the 15% tyre drop...
<nods> Me too, Martin. Frank Berto developed this concept after interviewing a number of bicycle tire makers.
A PDF of his original article is here: http://www.bccclub.org/documents/Tireinflation.pdf
Jan Heine's _Bicycle Quarterly_ article based on Berto's work is here: http://www.bikequarterly.com/images/TireDrop.pdf
For some posts related to this, see:
http://thorncyclesforum.co.uk/index.php?topic=3795.msg16351#msg16351
Helpful posts in this topic and on the pages before and after:
http://thorncyclesforum.co.uk/index.php?topic=3798.msg58373#msg58373
More is available using "Berto" as a Forum archive search term.
http://thorncyclesforum.co.uk/index.php?topic=11829.0
http://thorncyclesforum.co.uk/index.php?topic=8451.msg57241#msg57241
Our own JimK took a stab at the topic with a pressure chart here:
http://interdependentscience.blogspot.com/2013/06/bicycle-tire-pressure.html
For those who would like ready access to recommendations based on Berto's work, the Bicycle Tire Pressure Calc (Berto Tire Pressure) Android app by Edison Gauss Publishing recommends pressures remarkably close to Berto's original 15% drop charts and my extrapolations and has worked consistently for me. My bikes all have drop handlebars, and the "French randonneur" frame/setup option is closest to my needs.
Free version: https://play.google.com/store/apps/details?id=com.edisongauss.bertotirepressure.demo
Paid version: https://play.google.com/store/apps/details?id=com.edisongauss.bertotirepressure
http://www.edisongauss.com/index.php/berto-tire-pressure-app/
Notes here wrt frame type and weight distribution:
http://www.edisongauss.com/index.php/customer-support/#tpCustomGeometry
Hopefully helpful,
Dan.
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I too seem to have been "unlucky"
While away the wife's rear wheel started to grab when she braked.
Thinking it was simply out of true or dirt, eventually found a hairline crack as well.Same as the photo but much smaller.
Can only imagine what that handled like.
I did try to get warranty but because I wasn't the "original owner" had to cough up. Like that made any difference. The The company that makes them never responded so dealt with SJS.
Questions about tyre pressure, wear and tear and general use were asked. Like that would make any difference. Did they get wet and what about dirt roads. Seriously?
Hey, these are top of the range rims and the wife is a light rider, but no way.
Had to buy another one but this time a Andra CSS like I have on my Raven. Even though we had purchased 2 bikes, no discount. The rims themselves are a difficult item to buy.
The grizzly wall thickness is a bit smaller than the Andra.
So can only sympathise.
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As ever, thanks for the information - from what you have said and looking at Thorn brochure and 15% theory, I probably did have the pressure too high.
And yes, I had to stop using the bike as it was a bit dangerous when the rear wheel locked under a modest braking pressure! Most strange situation.
I have ordered some Swiss Stop green pads for aluminium rims, do they really reduce rim wear? I have used the blue ones and have been impressed.
Thanks again,Tim
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I've used the blue pads exclusively on the Andra and after 15000km there is no wear on the rims.
Expensive but good.
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I am now up to 30,000kms with the Andra rims - still only minimal wear on the brake surface.
The rims at 19,000kms:
(http://i1327.photobucket.com/albums/u666/petesig26/Stray%20shots/Rims%20at%2019000_zps8dop5tyl.jpg) (http://s1327.photobucket.com/user/petesig26/media/Stray%20shots/Rims%20at%2019000_zps8dop5tyl.jpg.html)
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Are they CSS rims?
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Yes they are.
Mine are the same as the photo and have about 15km .
Never been adjusted ad are true. Taken them through northern India, China over some rough roads. Pads seem to last OK.
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I think you may have just been unlucky to have the 2x Grizzly rims crack/ fail. Quite rare I suspect - I've had about 3 pairs in almost daily use for over 6 years without any structural problems.
Update:I wouldn't say spoke too soon, however I have had both my Grizzly rims crack internally between the spoke holes this year. I think I got my monies worth out of them though.
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i checked my previous rims today, those are also Grizzly from rigida (ryde now) with around 2000 miles only !
The rear rim is cracked on 4 point
(https://i37.servimg.com/u/f37/19/07/93/69/th/p1110418.jpg) (https://servimg.com/view/19079369/135)
(https://i37.servimg.com/u/f37/19/07/93/69/th/p1110419.jpg) (https://servimg.com/view/19079369/136)
(https://i37.servimg.com/u/f37/19/07/93/69/th/p1110420.jpg) (https://servimg.com/view/19079369/137)
Does it mean i can't reuse my rim ?
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I bought my Sherpa back in 2012 with Rigida Grizzlys on them. They gave me 12000 miles and still have probably 4000 miles left on them ( I just changed them to be extra careful as I was going on a longer tour).
The new set I bought were under the new "Ryde" name and I noticed the build was different. They don't look as strong or as finished as the original set I had.
I wonder if this is a factor ?
I hate it when you have a good product and they change it to save a few pennies .
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Does it mean i can't reuse my rim ?
I would not reuse them, Julien.
Superb photos, by the way. Clear and crisp as can be!
Best,
Dan.
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Those rims look knackered to my eye,contact the makers maybe they will replace them ,worth a try.
anto.
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I written to Ryde company, see if they want to send me a new rim :)
Otherwise, it maybe repairable with a aluminum welding ?
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I written to Ryde company, see if they want to send me a new rim
Nothing ventured, nothing gained, and it can't hurt to try. That said, it is possible Ryde may claim the cracks are evidence of past overpressure and so deny the claim. If this happens, you are at a dead end with them. Otherwise, it maybe repairable with a aluminum welding ?
Rims are extrusions and solution heat-treated (grain structure normalizing as they are formed, then cool as they are wrapped in a hoop after emerging from the die).While it is possible to TiG-weld the seam (crack), it would be hard to control for localized heat distortion and very difficult to grind the resulting bead flat within the confines of the rim well.
If you have a TiG welder and want to do it as a hobby, fine. However, for the cost and effort required, I think it would be better to replace the rims with something else and call it a day.
All the best,
Dan.
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i would not trust a weld on those cracks ,to be honest i would bin them put them down to ex perience :'(
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I written to Ryde company, see if they want to send me a new rim :)
Otherwise, it maybe repairable with a aluminum welding ?
Do you want to be going down a hill at 30 km/hour when you find out that the weld was not as good as you were hoping it was?
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;)too true
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Not unless you like hospital food.
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Just recently had a crack develop in my rear Ryde Grizzly.
It was either side of the valve hole.
They only had 2000 miles on them.
I contacted SJS and after sending them a couple of photos and a phone call they kindly sent me a new wheel out to France where i am.
I mentioned in a previous post on this thread that the build quality of these new named "Ryde" rims dont't look anywhere near as good as the previous "Rigida" incarnation.
My previous Rigida Grizzlys had a final total of 16,000 miles on them before i changed them( they probably had a few more thousand on them too). They were as true as the day i bought them with the bike.
Others that are quoting high mileage are also probably talking about the Rigida version not te Ryde version, which are noticably different in quality build.
Why do companies do this ? They have a good reputaion and then sell out and try to go cheap.
Well done to SJS / Thorn for the replacement though. At least I can count on them.
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I just passed 16,000 miles on my original (Swiss blue) brake blocks! I don't pay any attention to my rims! Rigida Andra 30.
Sorry to hear about your Grizzlies. That is really disappointing!