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Morning,
So, to cut it short, had to recently re-lace my wheels due to rim damage, which was expectable as the Flow EXs had a couple of seasons under the belt.
Laced my 350 hubs to DT E532 rims (29), 2.5 front and 2.3 rear Exo DHFs and a Huck Norris insert in the back. Was on 21psi front, 27psi rear. I weight about 92k.
Second ride with the wheels, actually first ride on proper challenging trails, do first sizable jump of the day, a small(ish) 4m gap and all air is gone from rear wheel.
Inspection showed a sizable dent on the rim, tyre was not damaged, insert showed no signs of cuts or crushing. Was quite frustrated, thought the Huck Norris would protect better. Managed to hammer the rim back into shape at home, seems to be holding air OK.
I know a tyre insert is not a force field, specialy one as minimalistic as the Huck Norris, but come on, this was no big deal of an impact.
Was my rear tyre pressure too low? If I get over 30psi my rear end starts to misbehave, I ride mostly natural trails. What are people's experiences with Huck Norris? Anyone sharing the same?
I run with them but on carbon rims. I'll be replacing them before the Alps because they're pretty beaten up. I'm of the opinion that they'll reduce small dings but if you smash a rim into the ground with enough force to blow the air out, or on a flat tyre, it's not going to help.
Was my rear tyre pressure too low? If I get over 30psi my rear end starts to misbehave
That just needs practice, it's not misbehaving it's just behaving differently.
As for the insert I've been running one in my rear for a while and it takes the edge off of a lot of things but it's never going to fix physics. If you've bent the rim you hit the ground hard*, I'd expect the huck to reduce that but really IME they prevent sharp impacts damaging tyres and rims by by that I mean pointy sharp.
*If your rim has bent without damage to the insert or the tyre though I'll be honest my first inclination is to say the rim or most likely wheel build is at fault.
Ive been using Nukeproof ARD and had no issues at all. Huck norris looks pretty flat so i doubt it would give much protection.
your rim has bent without damage to the insert or the tyre though I’ll be honest my first inclination is to say the rim or most likely wheel build is at fault.
What did he do wrong when building the wheel that it meant it caused his rim to bend easily.
What did he do wrong when building the wheel that it meant it caused his rim to bend easily
Most of the strength in the wheel comes from the spokes, if they're not tensioned properly or sized correctly etc the rim flexes a lot more than it should and bends (try squashing a rim only vs a whole wheel). I haven't seen the wheel in question nor how it failed but, given the lack of impact damage (and huck norrises get pretty cut up) my first thought is something at fault not just landed badly.
I'm also expecting the op ran wheels without huck norris previously and rode similarly with similar pressure and no problems, so the implication is if its at fault in any way the huck norris caused the problem. Changed? Unlikely. What else changed, rim? Possibly some are less sturdy than others. Build, most likely, a "bad" build is always weak.
The rim was dented. Nothing you can do with the spokes or the build will cause or stop that.
Very relevant questions raised regarding the wheel build, I would raise them myself had I not seen the actual damage. However, I don't think wheel build to be the root cause of the problem, for 3 reasons:
- the wheel was laced by a very reputable specialist, but this is worth a grain of salt, everyone messes up sometimes;
- the damage was in an area between spokes
- there was minimal radial deformation. Most of the damage was the "hook" is the rim (vertical wall) flaring out a good deal
The insert was not the only variable in my experience:
- was using, like I said, Flow EXs rims, now DT E532
- different bike with slightly shorter reach (500 Vs 475mm) might influence a more rear biased weight distribution on landing
- track felt more rocky than the last time I rode it, mostly related to rainfall
Most likely you just got unlucky then. The huck norris isn't bullet proof but if you've ridden the same track etc before and not had the problem certainly the huck won't have made the damage more likely than before (guessing you weren't running anything before).
The dt rims are well regarded (I've had less good experience with stans in the past but that's a while ago). I believe stans use very low beads though so possibly more resilient to impact?