Cracked rear rim on Raven sports tour

[Steve Lord]

That's it. So, freely admitting I'm a dummy for not looking into this further, but taking it on Thorn's recommendation, I'm curious why they do spec the EX721. I'll have to ask them if they don't surface soon on this thread.

[tynevalleycommuter]

There is an interesting thread on the same subject (Mavic rims with Rohloff hubs) on www.tandem-club.co.uk on the discussion board which is searchable. This seems to indicate that Thorn may be starting to make available 40 hole rims with specially drilled Rohloff hubs for tandem use. Could also be useful on solos for heavily laden touring (or very large riders!)

David

[Swislon]

Thanks for this info Stuart. I am learning something new all the time here. I've 717 on my RST but didn't think about tyre size and tyre pressure when I specced them. I better make sure I don't go above 88psi.

By the way re slicks I've got some WTB Slickasorous 1.5" from LBS, JD Cycles in Ilkley. John the owner highly recommends them, £13 each.
I haven't put them on yet but will let you know how I get on.

Steve

[stutho]

Well it's finally gone,

After about 12000 miles (10,000+ on the RST) my ceramic 517XC has finally died a spoke has pulled through.  It has spoke hole cracking for at least the last 6000miles.

Now do I go and buy a 717XC ceramic (to match my front wheel) or get a  Rigida Andra 30 Tungsten Carbide with the Rohloff drilling patten.  The Ridgida are much cheaper and probably more robust but the Mavics are lighter, I can use the existing spokes and I like the 717's. My front wheel (717 not 517) is in great condition and has seen a similar mileage to the rear.

Incidental I wasn't riding my bike at the time the rim went - I was carrying it when I slip.  The rim saw a large lateral force and a spoke popped

In these last  last few months I seam to have has an unreasonable number of problems with my RST - I broken my saddle, a set of Avid Ultimate callipers -  , and now a rear wheel.  The frame is as good as ever and so is the Rohloff so it's not all doom and gloom.

[Al Downie]

Now do I go and buy a 717XC ceramic (to match my front wheel) or get a  Rigida Andra 30 Tungsten Carbide with the Rohloff drilling patten.

I'm about to take my back wheel to a wheel builder to get it rebuilt after a spoke blew on me yesterday snapped about an inch away from the nipple). Never happened to me before, but I've never been this heavy before, I guess. I bought the wheel (because it had a Rohloff hub) on Ebay, so I don't know its history and I've lost a bit of confidence in it now, so I'll get all the spokes replaced, and maybe even consider a new rim while I'm at it. The chap I spoke to mentioned that he had Mavic 717 and 719 in stock, but this thread has put me off a bit!

Can I ask - what is the 'Rohloff drilling pattern'? I've been slightly suspicious of the way my existing spokes exit the nipples - they exit at a fairly sharp angle to the line of the nipple, but I've always shrugged that off as an inevitable feature on a wheel with a large-diameter hub. Is there some advice I should pass on to the wheel builder, in case he's not familiar with Rohloffs?

[geocycle]

Hi Stutho, what happened to the avid ultimates?  I got one replaced under warranty because a tiny metal boss that the fine adjusting screw pushes against broke off on one caliper.  This disabled the brake as I couldn't keep it off the rim.  I went ahead and bought another straightaway (hence the replacement being oferred below in the small ads).

[freddered]

A Rohloff drilling pattern has slightly 'cambered' holes so that the spokes point more directly at the flange and don't need to bend as sharply as they exit the rim. 

I don't think my CR18s have them and I never broke a spoke (actually never in my life).

I think the Rigida Andra Carbide will be my next rim.
I'm not too sure about the front but I reckon they will make my rear wheel into a 'fit and forget' item.

My Rear CR18 lasted just under 8000 miles before the sidewall caved in and cracked.  I tend to drag the rear brake on long steep descents which won't help but the main problem is riding on gritty country lanes in all weathers.  It's quite hilly round here so you tend to be climbing slowly or descending quickly.  Brakes/rims take a beating.

[stutho]

Geocycle,
That sounds like exactly the fault that I had.  I have to admit that it was totally my own fault I was temperately switching the callipers over to a suspension forks.  I was in a hurry and I tightened down that little metal prong onto the adjustment screw snapping the prong I was not a happy person for the rest of the day - I hate braking kit through stupidity. 

[geocycle]

Sounds like a bit of a weakness on what is otherwise an excellent product.

[stutho]

Al Downie,

The chap I spoke to mentioned that he had Mavic 717 and 719 in stock, but this thread has put me off a bit!

I am still a fan on the 717 Note the wheel I just damaged was a 517.  I have built up 5 wheels with 717 rims - All are still true even after some abuse.  The thing with rims is that there are different horses for different courses.  If you intend to use the bike for heavy off-road touring  then maybe this is not the rim for you.  If like me you  spend 98% of your time on tarmac then the 717 it is a good bet.

Re Rohloff drilling pattern,  its a freddered said.  
If you build up a 717 with a Speedhub then the spokes wont line up properly with the eyelets. HOWEVER if you are careful during the build you can slightly cold set the eyelets with a metal rod. (Credit to Andy at SJSC) PLEASE proceed with caution and don't blame me (or Andy) it goes wrong.  There are many times more wheels out there with speedhubs that don't have the correct drilling patten than those that do so don't be too concerned about it.  

  

[jawj_uk]

Howdy all,

Bit miffed to see the original post about the 717 cracking. I for one rejoiced and celebrated when that rim was released. It's vastly different from the old 517 in that it has what Mavic call "H2 Technology": Hammer Hardening. This is where they 'hammer' the the heck out of the rim around the spoke holes before installing the eyelets to make the metal stronger and less prone to cracking.

Why did I rejoice? Well, a highly strung wheel (i.e. with the spokes at higher tensions) is a stronger and longer lastly wheel. The 517s couldn't be built that tight without cracks appearing in not too much time.

And as for the 717s? I love building wheels with those rims. I've got several myself and you can take the spoke tension to a lovely and tight 1100N and they roll true and straight with no broken spokes forever and ever and ever.

EX721: These are my rims of choice for touring as you can put wider tyres on them than on 717s. I've used loads over the years and they've all died from being worn out (the braking surfaces aren't that keen on the constant stop-start of commuting in all weathers). I now use a disc brake on the back of my Raven Nomad. I've used Sapim Race double butted spokes and have 'abused' the wheel quite a lot with no cracks, broken spokes or out-of-trueness. As for tyre pressure, I've a Schwalbe Marathon 2.0 on the rear and have run it at 80psi for over a year with no problems.

A note on spokes: in my youth I was instructed that plain guage spokes were stronger so when I first built up a Rohloff hub to go on my mountain bike I used Sapim Leader, non-butted spokes. I had two spokes break inside a year. Then I learnt the truth about spokes: wheels built with double-butted spokes are stronger and last longer. When the rim wore out I rebuilt it with double-butted spokes and it's been beautifully wonderful since. 'Course, now I've said that I'll probably start snapping spokes all over the place. I've recycled the 721 that wore out onto a disc brake wheel and have given it some punishment. It doesn't seem phased that it was previously built on a Rohloff and so had the spokes arriving at it at a very different angle.

A note on messing around with the eyelets on your 717s: stuff that! No offence to Andy and to wheels that have had it done and survived, but those rims are precision made and I wouldn't want to mess around with what those clever Frenchies have done. Wheel building's all about using decent spokes and nipples and getting the correct tension (i.e. as high as the weakest link can take). I've found that Sapim's brass nipples have enough of a rounded profile around the head for large flange Rohloffs not to be a problem.

Congratulations of you're still reading and I hope some of this is of help to someone. :-)