Laterally Stiff Carbon Wheels
bigburnsgeoff
Posts: 35
I've got a pair of Reynolds Assault and Strike SLG's carbon clinchers that are both <2yrs old mated to my Ridley Noah SL. Having had most of 2016 off the bike due to illness i'm back on it with a vengeance. But the old frustrations come back.
I'm a 90kg rider and both sets of Reynolds wheels display the same characteristic in that when i'm climbing or out of the saddle giving it some, I get really irritating levels of brake rub. I've set the brake pads back as far as possible. I've had the wheels checked for spoke tension and ensured there is minimum play in the hubs. However at the rim you still get excessive lateral flex that results in brake rub giving you that annoying noise in the knowledge that its sucking away your power. Given that it is present in both sets of wheels and I have had everything checked I have come to the conclusion that it in the design.
Has anyone got similar experience?
Who makes carbon wheels (40-60mm deep) that have the least amount of lateral flex?
I'm a 90kg rider and both sets of Reynolds wheels display the same characteristic in that when i'm climbing or out of the saddle giving it some, I get really irritating levels of brake rub. I've set the brake pads back as far as possible. I've had the wheels checked for spoke tension and ensured there is minimum play in the hubs. However at the rim you still get excessive lateral flex that results in brake rub giving you that annoying noise in the knowledge that its sucking away your power. Given that it is present in both sets of wheels and I have had everything checked I have come to the conclusion that it in the design.
Has anyone got similar experience?
Who makes carbon wheels (40-60mm deep) that have the least amount of lateral flex?
0
Posts
I came to the conclusion that it was the frame that was causing the rubbing when the brakes were set too close and that stiff frames would induce more brake rub than less stiff frames. My frame is a 2011 Felt F5 (same frame as the F4 and F3 of that year) and while I don't find it too stiff, it is apparently a very stiff frame. The Noah is supposedly a very stiff frame also, so perhaps that's why you get brake rub, if the frame allows no flex then the wheels are going to soak up all lateral movement and cause the brakes to rub on climbs/sprints....maybe.
I'm gonna sound like a broken record, but get some hand-built wheels, made for your weight and riding style. Speak with Derek at www.wheelsmith.co.uk and tell him your issues. Cheaper than factory (usually), replaceable rims, easy servicing, good service. The only thing you won't get is some fancy stickers..
Kinesis 4s Di2
Having got so irritated in the rain and and road muck that was present on UK roads yesterday i've already started to look at the custom option but keen to see if there is an off the shelf solution.
Cheers for the input.
With any 50mm ish deep wheel and i dont care who makes it the pads must be 2mm from the rim or brake rub may result. There is no good way around this. One solution is tom use a single pivot brake for the rear. This is the set up i have on two bikes and it works a charm. Even with the pads 2.5mm from the rim the levers dont pull back to bars.
So buy a single pivot brake or get used to a lever than pulls more than you prefer, new wheels may not make a huge difference.
So the op has said he has set the pads as far from the rim as possible but how far is that.
Stiffest wheels I've ever seen. Top of a French magazine test, way above all others for lateral stiffness. I have a pair and they are way stiffer than my Lightweight Meilensteins. Too stiff for me in fact, a bit unforgiving.
But for a big, powerful rider, perfect.
It all sounds like a lot of baloney... both the eroic efforts that bend the rim and the proposed solutions to the perceived problem
Odd you should say that, tales of rims touching brake pads on out of saddle efforts are all over the place.
Personally, and unfortunately, I don't make enough power to bend mine significantly, but I totally get it for a 90kg sprinter.
That French mag test applied weights and stresses to the wheels and measured lateral deflection at the rim with a wide range of performances from different wheels.
I know, I experienced it myself... was it a major problem? No
Was it something I lost sleep over and even more importantly lost speed over? Not really
Would it be something that make me part from a set of wheels worth in excess of a grand? Certainly not
Would a different pair of the same thing make such a massive difference? Probably not
In essence, even if the pads lightly rub the rib whilst climbing out of the saddle, it really is nothing to worry about... in this respect, It is indeed all baloney
What the pro's will have probably isn't all that similar to what we can buy in a lot of cases, I've had brake rub putting out similar peak power to Sagan assuming its around 1600w, I don't know whether I can be arsed to get it looked at and most of the time its just been hub preload that needed attention. But you know 100% that if he or any of them ever had any issues then it would be fixed, more spokes, welding them together (which is what Griepel had?) or whatever, its not going to be an issue for them.
...but that is where I am coming from, as in, how do they resolve this in the pro peleton? The number of spokes is not the solution if one looks at the sprinters wheels. I don't see any cross bonding in place and most of the wheels do indeed look to be off the shelf (although looks can be deceptive).
Perhaps the simplest fix for the pros is they just back off the brakes in the last 5 km??
IG: RhinosWorkshop
Being a rider for 30 years, and also an experienced mechanical/engineer, I have a well looked after crop of bikes. Whilst some maybe happy to have a bit of brake rub (I have in the past) when it becomes excessive (allowing for (7mm+ of pad offset) I personally find it annoying and it highlights a design weakness. These are the kind of things we dont except when we design aircraft, cars etc so why should I accept it on one of my bikes. You may not, but I do...It tends to be less of a problem, or no problem at all on my other bikes.
The point on the pro's is a relevant one. The monster amount of power that Griepel will generate will require special attention and I'm sure someone takes this into consideration. Whether he get wound-up by a brake rub on his sunday club ride is up to him.
WRT the Reynolds wheels, yes they are not cheap but they are not at the really expensive end of the carbon wheel market and I think this will contribute to the problem. At ~£1k more for a pair the Zipps may have a more robust engineering design, better assembly, lower tolerances and better materials. I may have to check them out or a pair of custom builds.
For everyone else who replied I appreciate your input and comment. thanks.
Crikey, 7mm is HUGE! Do they still rub at 7mm? If they do then that suggests a total of 14mm lateral flex which would indicate a problem, I believe.
Slightly off topic but what is the usual gap between pad and rim? I have always approx. 1mm gap although on some older wheels in the past I've increased that to roughly 2mm but nothing ever bigger.
If you go for a spoked wheel, given all rims on the market are very similar in size, what determines stiffness are:
1) bracing angle of the spokes, which is pretty much the same across the board
2) SPoke gauge, which is pretty much the same as they all use the same spokes
3) Spoke count, which is always the same 24 or 20 depending on rim depth
4) Spoke pattern, which occasionally is different, but it is the least important among all the parameters and to be honest it makes almost zero difference.
If you want a real difference, then you have to look at a non spoked wheel... something like the stuff Lightweights make... I am not saying the latter ones are stiffer, I am saying they are different, so the rules above do no apply.
Personally I would have your wheels checked in case the spokes have gone slack and if that's not the case, then I would assume that a similar wheel with a similar depth rim will be more or less the same thing. If you are an engineer, you certainly don't believe in miracles
I set mine up with a credit card in between the pad and the rim so that you get ~1mm of space which can work in an ideal world, and then maybe backing off the pads just a little further with the adjuster barrel. In an attempt to avoid the brake rub i have had to back my pads off a significant amount using the 3 step adjuster on the Sram Red calipers I use.
A neat trick is to partly slide the CC out from the pad and this then allows you to set a little toe-angle between the pad and the rim.
The other problems with the Reynolds is the tubeless compatibility. Its not great when compared to other wheels. Its clearly a bit of an after thought as you can see from the design of the rim at the point where the valve mounts. You can get them to seal eventually but its a faff and they are a bit temperamental. I have found other tubeless wheels to be much better in this respect. They also come in quite heavy (significantly heavier than its says on the packet anyway). But they're fast and brake well (for carbon anyway).
That is a very, very nice looking bike.