Hi,

I just wondered i anyone has experienced flats caused by Mavic rims. I've had new wheels & tyres on my bike for 2 months now and they are great, fast & light! I started getting flats nearly every ride but put them down to pinch flats caused by the new Kenda Nevegal 2.1 tyres.
Having looked at the tubes all the holes are on the innermost side that would contact the rim tape. Thought it might be the eyelets causing the punctures (they do seem sharp), so I cut up one of the old tubes and used it as a second layer of rim tape on the rear tyre.
Done 1 ride since and the rear was fine but got a flat on the front with same problem. Should i bastardise another tube to protect the new front ones?

Cheers.

I had a similar problem a while back with my rear X317 rim.There was a split in the rim under the tape, it wasn't visible till I removed the tape.It punctured 3 tubes in exactly the same place, best to get it checked, you don't want a wheel exploding on a downhill.

Are you sure it's the rim?

Sounds like it may be a spoke protuding slightly and the pressure in the tube pushing the tube wall into the eyelet hole against the spoke tip.

I've had this happen with a couple of wheels in the past but since I've bought my wheels from Merlin. (no, I don't work for them).

I have these rims and am havig exactly the smae problem, rim isn't split though. Pissing me off now. I put it down to pinch flats as I'm using Intense wedges, 1.85 and they're much slimmer than anything Ive had before, but this comfirms it must be the rim. Maybe time for a different rim tape.

I have never had an issue like this on 717's. I suppose removing the rim tape & running yer finger along the internal metal will tell you if anything is protruding.


If the cut up innertube has solved the problem it would indicate that something is protruding which needs sorted. I wouldnt be happy at the extra weight of the cut up tube as a solution.

What size innertubes are you using?
you could have thin tubes or they may be 1.95 inners used with 2.1 tyres.

Could be tubes.I've used some WTB lightweight tubes in the past and they were notorious for just splitting where they contacted the rim tape.

My problem with 717's is different. I have panaracer fire xc pro tyres and 717's on two bikes, and the bead has come off the rim twice now. It's not a bad batch of rims or tyres as the two sets were bought 12 months apart. I run about 35psi in the tyres too so it shouldn't have come off! Anyone else had this?

Defo seems like the eyelets have sharp edges. Enough so that if the rim tape isnt doing its job it will split the tube.
Hobo, I was using 1.5-2.1 geax tubes, fairly light so may go for something a bit thicker but that would be adding about the same amount of weight as a cut up tube!
Had the wheels built by CRC so good rep there and the spokes seem nowhere near the tube side of the rim.
Think I'll try some more cut up tube on the front, if that works I'll swap it for some higher quality rime tape, any suggestions to make?
Thanks all for the input.

Bit of wt & dry paper round the eyelets then if its rough, although i would be inclined to send them back if thats the case cos it sounds like a friday night rim.

CRC have built my last 2 sets of 717s and never had this prob, am just trying a merlin built set and they dont have a rough surface round the eyelets either.

Mojo, i have heard this before and cannot understand it. I have ran 717s for 5 years with fire xc pros. Although i think anything below 40psi in this format is asking for trouble imo i still cant see the tyres coming off the rims. I only ever got close to this using 2.35 kendas.

You are either mega fast & hard or you have them at even lower pressure than you realise. as i said, i run mine at 40 psi and even at 30mph i cant feel any mvement like that

Cheers Hobo. May try to round off the eyelets a little. Friday night rim maybe (!) but you'd think the QC pass was on the Monday morn (or maybe QC passed them on Friday night!?!?! Hmmmmmm). It both rims anyway........

Surely if this IS a problem with the 717 rims (see Pjordan's post)a lot more people would be having the same trouble.
717s are light weight XC rims so you'd think the majority of users will be using light weight (i.e. thin) tubes and folding tyres. I did get the wheels built with the cheaper spec rim tape rather going for the more expensive cloth, is there much difference?

Yes I've had 2 different sets of 717 rims and 2 different pairs of fire XC pros and have had them come off the rim once on each bike , they were run at 40+psi and no jumping or anything like that . I was also riding behind a friend and it happened to him . In all 3 cases the tyre bead had only come over the rim for about 6 inches and I stopped the first time because as I was riding it looked as though the wheel had gone out of true , the second and third times were the same but I knew what to look for . I did post on this forum about 2 years ago regarding this but was surprised that loads weren't having the same problem . I also went ages with no punctures but then started getting them every other ride or if no puncture I'd put the bike away and next day the tyre was flat and these punctures came from the rim side of the tube but I never solved the problem so I converted to tubeless with an Eclipse system and Bontrager Mud X and ACX tyres , no more punctures and better grip than the Panaracers and no tyres coming off the rim .

I would try the better rim tape sean. Checked mine yesterday and they are the cloth rim tape (3rd set of wheels it has been used on). I checked round the wheel and can see no way of it effecting the tube with this on even if the edges are slightly rough.

Neil, agreed. As i said i have read numerous messages with the same story as yours. Just amazes me that i have been so lucky.

The stuff suggested here is the stuff i use.

Link

sean the easy way to find sharp edges is to use a ball of cotton wool and run it round the rim clumps of fluff should collect on any sharp bits.

As for the tire rolling off the rim use a cloth rim tape and chalk the tube and tire to alow them against each other evenly not stick together. (or so someone recomended it to me) and as hobo says run at a slightly higher pressure and check they are are seated properly

Cheers Hobo.
Andy, I'll try chalking the tubes too. I think the rim tape and tube must be sticking coz sometimes I get home after a ride and all seems ok. The next day the bike is sat in the garage with a flat! The tube must be semi-sealing against the rubber rim tape.

try cloth rim tape or failing that a couple of wraps of electrical insulation tape. That shouldnt move..