- This topic has 29 replies, 11 voices, and was last updated 5 years, 1 month ago by
.
-
Topic
-
Running (Specialized) RovalCL50 wheels with Enve SES TLR 25 tyres (75psi front). Last Sunday I hit a series of small potholes through Epsom, (I’d say I’ve straight-lined worse in the past with no worries), front went bang (tyre didn’t puncture though) and I went down hard.
When I picked up the bike the front tyre was inside out. This tyre’s done 4.5k, is in roadworthy condition, no repairs/tyre boots/plugs. New sealant and inspected recently. The Enve tyre and Roval rim combination makes fitting fairly easy using a single lever or even just strong thumbs and a good push. Maybe that’s a red flag but hearing horror stories about tricky GP5000’s from many I thought I was onto a good thing. Needs a compressor or tubless inflator to seal. Tyre doesn’t need a hookless rim. I just don’t understand how it could have come off if rim & tyre are in spec.
Lots of road rash, trashed kit, cracked frame and smashed levers etc. Wheel actually looks like it might survive despite the fact I was just rolling on the carbon momentarily (which sounded horrible) before going down.
Thankfully I didn’t take anyone else out, didn’t hit the kerb or get collected by a car. I have bike insurance, I have other bikes and after a couple of weeks of healing I’ll be hopefully ok to ride. But it could have been very different.
So far some have just blamed the fact it’s tubeless. If any one has any constructive thoughts beyond this I’d love to hear them. My take is that this is a rim/tyre design or manufacturing failure and I should take it up with the manufacturers.
However the fact that Specialized has abandoned tubeless on the SL7 is not lost on me.
-
Over the past couple of weeks
Over the past couple of weeks I’ve been able to speak directly with ENVE. Together we went through the sequence of events and the sensations I experienced from the front of the bike and they looked at the photos of the road condition and the tyre.
The consensus arrived at was :
1-Tyre burps on the first pothole strike and the sidewall is pushed into the centre of the rim
2-Total loss of pressure causes tyre to blow off and flip inside out
3- I ride on the inside out tyre. The rim pressure against the road causes approx 30 cuts* along the tyre bead-protecting the wheel rim hence the lack of damage to it’s circumference
4- As I fall, the side of the rim picks up some damage to one area only.
They then helped walk me through a tubeless rim design as defined by the ETRTO standard, and I can see how ENVE’s design of their tubeless rim offers additional protection against the problem I experienced. Comparing cross sections of say the Roval, ENVE and Hunt’s Limitless, the Roval bead shelf is much narrower, the centre channel much wider (and shallower) and there is no hump between the two. I’d guess the situation is compounded by running a 25mm tyre.
We also looked briefly at the ETRTO standard that was current when Roval released the CL/CLX which (from memory )mandated the ‘hump’ between the shelf and the centre drop (it doesn’t anymore for some reason, maybe a widened bead shelf). As such, I’m not even sure that the rim was ETRTO compliant and I will research this further and follow up with Roval. I contacted Specialized via their ‘Rider Care support’ link but I’ve still not heard anything. I’ll post more when I do.
*Initially I couldn’t see much wrong with the tyre and couldn’t wash off the sealant to inspect properly as my right hand was covered in dressings. When I did, I found approx 30 cuts alongside the bead
the inside
the inside
The road surface:
The road surface, postition wise I was riding primary:
- You must be logged in to reply to this topic.