Beware Grizzly rims!

[mickeg]

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.

[tt2cycletours]

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.

[Danneaux]

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.

[martinf]

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.

[Danneaux]

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.

[onrbikes]

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.

[tt2cycletours]

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

[onrbikes]

I've used the blue pads exclusively on the Andra and after 15000km there is no wear on the rims.

Expensive but good.

[il padrone]

I am now up to 30,000kms with the Andra rims - still only minimal wear on the brake surface.

The rims at 19,000kms:

[in4]

Are they CSS rims?

[onrbikes]

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.

[brummie]

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.

[jul]

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 





Does it mean i can't reuse my rim ?

[bikerwaser]

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 .

[Danneaux]

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.