2nd time my front tyre (Rene Herse Bon Jon Pass 700×35) has blown off my rim (Enve SES 3.4).
Relatively low speed, fortunately.
Tyre pressure was 80 psi before setting out – max spec for the rim. Ambient temp is ~70+ degrees F.
Is this a case of needing to reduce tyre pressure on warm days? Or some other issue?
Tyre has approx 500 miles on it.
Advice welcome on likely rim damage. Looks to be mostly aesthetic.
Thanks!
by naogorma
27 Comments
the max recommended tubeless pressure on those tires is 60psi
What’s your weight? Pressure sounds high. I would reduce to 50-60 psi and go from there. And no, 80 psi most likely will not be any faster.
Pressure is too high. Max should be around 60 if tubeless
Search for a tyre pressure calculator to c as package what’s right for you/bike/tyre combination.
Silca do a decent one
80psi on 35c tire, that seems like ridiculously too much ( i run 75psi front and 80psi back on 28c road tire). Try 60-65psi. I assume you dont weight 120+ kg or something.
Glad you’re ok, sorry to hear this.
I’d review the tire compatibility with that type of rim very carefully before using again. Check Enve and RH’s webpages.
Inspecting the rim edge and tire bead is also strongly recommended, any breaks or cracks should then be reviewed by a shop.
Finally, 80 psi for a 35mm tire is very high, you’re missing out on serious comfort, speed and grip improvements.
For me, at 180lbs and with a similar set up but different brands, I was running less than 50 psi.
Check an online psi calculator for better clarity.
Hope this helps and you don’t have this issue again.
Problem 1 is running Rene-Herse. Problem 2 was running them at 80 psi. Problem 3 was running a tire again after its blown off. If you don’t want to solve problem 1, get another one and try closer to 60psi. Once a tire blows off the rim it’s done for. That kind of trauma to the bead renders it unsafe
>Tyre pressure was 80 psi before setting out – max spec for the rim.
max spec for the rim when using tubes
I don’t run that high of pressure on my *tubed* 35mm. Or my tubed 30mm.
Glad you’re ok
Go for a hooked rims
Should be running pressure much, much lower
This illustrates one of the issues I have with the hookless standard. You may well be right that the rim indicates a max pressure of 80 PSI. You may want to look closely at the sidewall – is there any text around there? Also, does your manual give any specifics?
The ISO standard (reproduced by Schwalbe [here](https://www.schwalbetires.com/technology-faq/hookless-rims/), shows that for a 35mm tire, the maximum permitted by the standard is 58 PSI, not 80. If you Google maximum hookless tire pressure, you might see a figure of 72.5 PSI – that is correct for 25-29mm tires.
I want to say you should have checked this information before mounting that darn tire. However, it is a lot of information, and some of it seems contradictory. Also, Enve may have rigorously tested the rim up to 80 PSI and indicated that on the sidewall, but they should have also indicated what tire width that applied to. I don’t have Enve wheels so I can’t say this for certain.
At the same pressure, a wider tire has a lot more casing tension than a narrower one.
I made the same mistake when switching from tubes to tubeless. The pressure is pretty high. 80psi would be fine for tubes, but on tubeless I don’t exceed 60 on 35c tires (s-work Mondo) and even then it seems too hard
Firstly, and most importantly, the maximum pressure on a hookless rim is 72.5psi. Secondly, even though the tyre is hookless compatible, it’s not in Enve’s approved list. That said, I don’t think that’s actually a problem – more just a point of technicality. If you tried to make a warrantee claim on the rim though, Enve would call you out on both issues.
Where’s the sealant? I don’t see a drop of sealant anywhere, it’d be splattered everywhere if you blew out
First, too much tire pressure for a tire that size and on a hookless wheel. Generally the max for hookless wheels is around 72 psi (a tire this size is probably less).
Second (as a bike mechanic) I don’t recommend using rene herse tires and enve wheels together. I’m not sure the tires are on enve’s approved list. Also it’s a combination that has given me the most problems in when trying to do a tubeless set up in the shop. The times I’ve tried to set up this combination the tires fit so loose on the rim that I’ve recommended to the customer to try something else because I wasn’t sure how well the tire would stay in the rim when it was being ridden.
Insanity. Surprised that the rim didn’t get destroyed already. 40- 50 psi is max you should try. Tire bead probably compromised now.
80 psi tubless? Are u crazy?
For reference, I weigh 190lb and run 32c tires on Enve rims at 50/55 psi front/back. 80 psi on 35s???? Holy shit that’s gotta be harsh.
Really compounding user errors here:
1. **The ETRTO industry standard max pressure for TSS (Tubeless, straight side aka hookless) is 72.5psi.**
* Unless a specific wheel+tire combo is specifically rated for higher pressures, never exceed 72.5psi in a TSS combo (which must consider both the rim and tire).
* As noted by u/bill-smith, the maximum allowable pressure goes down with tire width.
* Examples of combos that allow higher pressure would be <29mm ENVE tire + ENVE rim, and Cadex rims with [validated high pressure tires](https://www.cadex-cycling.com/ca/hookless-rim-technology)
2. I**f in doubt about pressure combos, always defer to the lowest max pressure listed in a tire and rim combo.** In this case, that’s the tire at 60psi.
3. **80psi is an insane pressure to run in 35mm tires. I** weigh ~225lbs with gear, and run 40psi rear and 37psi front. I know I can easily run much lower without issue – probably 30psi rear before I start having any problems.
* Check out [https://www.instagram.com/flexfitbyjohn/](https://www.instagram.com/flexfitbyjohn/) – he posts extensive rolling resistance tests on different surfaces. IIRC, his baseline starting point for tire pressure is the ‘type 2 gravel’ setting in the [Wolftooth pressure calculator](https://www.wolftoothcomponents.com/pages/tire-pressure-calculator). He adjusts from there, but finds that gets him in the ballpark for lowest rolling resistance across all surfaces.
* That calculator will put riders of most adult weight ranges in the 35-45 psi range for the rear tire with a measured 35mm width (and lower for the front). **This means realistically your front tire pressure was probably 2x the ideal pressure for rolling resistance – i.e. running lower pressure will make you faster** (and more comfortable, and safer)
4. **Once a tire has blown off a single time, it’s garbage** (especially with hookless rims). There is a high likelihood the bead has been stretched or damaged, and the tire will never seal securely again (even if it looks undamaged.)
* If you absolutely insist on ‘getting your moneys worth’, the tire should be relegated to commuter duty – hooked rims, with inner tubes, rear wheel only (as a blowout on the rear is less likely to cause a crash).
5. The rim damage is probably just aesthetic, but if in doubt, have it checked out in person by an ENVE dealer, or send pics to ENVE for evaluation.
Drop your pressure. I run panaracer gk slicks in 35c at 40-45psi and never had a problem.
That’s WAY too high of pressure for 35c, and are those Enve’s hookless? If so the max pressure is 73psi and even then hookless wheels are prone to blowouts especially it seems with supply cotton cased tires (typically Vittoria Corsa Pro’s but I imagine the Rene Herse’s are similar).
I’m guessing with 35’s you should be running in the 50-55psi range anyways.
Damn dude. I run 50psi in my 35c tires at 210lb system weight. 80 sounds wild
put a tube…
You are running wildly too much pressure in HOOKLESS rims. Plus I don’t know if those tires are hookless compatible. Hookless and tubeless are NOT the same thing. This is not exclusively your fault but you need to take some serious responsibility for your safety and the safety of everyone riding around you. Your setup was wildly dangerous
Use tubes. Tubeless is dumb.
Pressure was way too high. You’re like me, used to old school high pressures.
I would run about half that pressure. I weigh about 80Kg and run 40/42 psi on 35mm tires on hooked rims.
Also, I’m pretty sure that ENVE does not recommend this tire for these rims. ENVE is very specific about which tires it considers to be compatible. I would get something else personally. While I personally love the feel of Rene Herse tires, they are minimally constructed and (in my opinion) barely tubeless compatible. You need to be careful with them.
That’s the problem with hook less rims even the pros have the same problem