new hand built wheel flexing

boborange

Hi,

Ive just bought some hand built wheels and was happy with them until my first real ride yesterday when tackling the top of yorks hill (20%) and standing on the pedals i got a bit of brake rub. I was not expecting this so when i got home i can flex the wheel from left to right several mm when putting not too much pressure on the tyre, is this normal ?

the wheels are H Plus son archetype rims (28h front and rear) with DT swiss 350 hubs and sapim laser spokes on the front and NDS rear and chunkier sapim spokes on the drive side (cant remember the name) with carbon ti skewers

ugo.santalucia

boborange wrote:

Hi,

Ive just bought some hand built wheels and was happy with them until my first real ride yesterday when tackling the top of yorks hill (20%) and standing on the pedals i got a bit of brake rub. I was not expecting this so when i got home i can flex the wheel from left to right several mm when putting not too much pressure on the tyre, is this normal ?

the wheels are H Plus son archetype rims (28h front and rear) with DT swiss 350 hubs and sapim laser spokes on the front and NDS rear and chunkier sapim spokes on the drive side (cant remember the name) with carbon ti skewers

I prefer to use chunkier spokes even on the NDS... even so, a bit of flex up Yorks hill is not the end of the world.. it is quite possibly the steepest climb in the south east...
People obsess about this brake rub... just keep the pads one mm further apart... I have a set of Ambrosio Formula 20 which are made of butter, yet keeping the pads a bit further apart there is no brake rub

smidsy

How heavy are you? How powerful are you? Perhaps 32 or 36 hole would have been better?

boborange

thanks ugo,

its the first hand built wheels i have had so not sure what to expect in terms of stiffness. the thing is i can flex the wheels a few mm between my thumb and finger by just pressing on the side of tyre.

Smidsey, im 78ish kg and would not say im that powerful

ugo.santalucia

boborange wrote:

its the first hand built wheels i have had so not sure what to expect in terms of stiffness. the thing is i can flex the wheels a few mm between my thumb and finger by just pressing on the side of tyre.

That's normal in 28 holes sets... you really need 36 if you want them firm. As I said, if they flex a bit up Yorks hill, I would not worry.. I remember the climb.. :shock:
If they flex when you are climb a steady 5% sitting on the saddle, then they are not for you.

boborange

thanks for advice,

they are fine when sat down on a steady 5-10% but when it got to the real steep stuff and i had to stand thats when i got brake rub.

to be honest i was more concerned that they flexed between finger and thumb but if that is pretty normal then ok as im happy with the wheel overall and look great with stickers off.

cycleclinic

With the 350 hub or the 240 for that matter thicker spokes are needed to avoid significant wheel flex. These hubs just do not give good NDS bracing angles which lead to poorer lateral stiffness with thinner spokes. Under the right conditions brake rub may result. This does not mean the 350 is a bad hub -it is not - it just needs the correct component selection to avoid brake rub issues but there are other causes of brake rub, mainly a wheel that flexes more than the frame or visa versa.

As ugo said lateral wheel flex is not a big issue just run the brake pads a bit wider. If the wheel had been built (and please don't take this as you should change your wheels) with a hub with 37 -38mm nds flange to centre spacing this issue would likely not have been present. I have built a number of such hubs with archetype rims and Laser spokes (28) both sides and the resulting wheel does not flex much at all under high torque. Given the stiffness of the archetype rim I would be surprised if the 350 hub built the way yo have described wold have a latteral stiffness issue.

So maybe its the wheels maybe not it is difficult to say really but ugo's assesment is correct rn the pads wider.

on-yer-bike

My Archetypes are 32 spoke on CK R45 boutique poser hubs with DT swiss Comp on the rear. No brake rub on Yorks Hill. Im a bit lighter at 72kg but have thighs like a North American Bison. They were built by a local artisan of some repute.

ugo.santalucia

on-yer-bike wrote:

My Archetypes are 32 spoke on CK R45 boutique poser hubs with DT swiss Comp on the rear. No brake rub on Yorks Hill. Im a bit lighter at 72kg but have thighs like a North American Bison. They were built by a local artisan of some repute.

Yes, but yours are 32 and I have had to fight a battle to fit you some proper spokes!

boborange

thanks for your thoughts.

I just dug out the build spec and on the rear drive side its sapim race spokes with lasers on nds with a 2 cross pattern. On the front radial pattern with lasers.

I appreciate the advice making the caliper wider will reduce/stop the brake rub but the flexing will still occur.

When i lift the bike and spin the wheel with no load on it there is a bit of movement (wobble) on both wheels of only a mm or two.

If this is normal for the build spec and budget (less than £400 built and shipped) then fine, im happy, i just need stiffer and probabley more expensive wheels. However if this is a result of a poor build then not so happy, i just need to work out if im expecting too much from them?

thanks

ugo.santalucia

boborange wrote:

thanks for your thoughts.

I just dug out the build spec and on the rear drive side its sapim race spokes with lasers on nds with a 2 cross pattern. On the front radial pattern with lasers.

I appreciate the advice making the caliper wider will reduce/stop the brake rub but the flexing will still occur.

When i lift the bike and spin the wheel with no load on it there is a bit of movement (wobble) on both wheels of only a mm or two.

If this is normal for the build spec and budget (less than £400 built and shipped) then fine, im happy, i just need stiffer and probabley more expensive wheels. However if this is a result of a poor build then not so happy, i just need to work out if im expecting too much from them?

thanks

Archetype rims normally build to perfection and stay true. Just a couple of nights ago a local guy I built some Archetype 28 for came here as he had some creaking noises coming from the rear, of course the clueless bike shop told him the usual horse-sxxt about creaking spokes and that he needed a set of Mavic instead... it turned out there was nothing wrong and it was the quick release a bit loose, but I had the chance to have a look at his wheels and they are still perfect... I was surprised to find a lateral offset of 0.2 mm after over 1 K miles, which is exactly the same as when I built them.
If wheels are well tensioned and you haven't crashed them or run into a foot deep pothole, they should stay true for many many miles... if they are not, then have a word with the builder and I am sure he will sort them out for you.
Going local is always the best way, as you don't have to send wheels, which is expensive and time consuming.

ugo.santalucia

To wrap up this topic, as Boborange turns out to work around the corner from me, he brought his wheels (build by JRA) here for me to have a look and there is nothing wrong with them... they are well built at very high tension... there is no "wobble".. the rims are true within 0.2 mm

Bar Shaker

ugo.santalucia wrote:

To wrap up this topic, as Boborange turns out to work around the corner from me, he brought his wheels (build by JRA) here for me to have a look and there is nothing wrong with them... they are well built at very high tension... there is no "wobble".. the rims are true within 0.2 mm

So you seem to be saying that flexing to the point of brake rub is normal for good hand built wheels.

Backing the brake pads off is all well and good for stopping the friction with the pads (at the expense of brake feel/response) but it won't stop the flex from sapping watts that would otherwise be going into forward propulsion.

I'll stick to my rock solid Ksyriums then.

ugo.santalucia

Bar Shaker wrote:

ugo.santalucia wrote:

To wrap up this topic, as Boborange turns out to work around the corner from me, he brought his wheels (build by JRA) here for me to have a look and there is nothing wrong with them... they are well built at very high tension... there is no "wobble".. the rims are true within 0.2 mm

So you seem to be saying that flexing to the point of brake rub is normal for good hand built wheels.

Backing the brake pads off is all well and good for stopping the friction with the pads (at the expense of brake feel/response) but it won't stop the flex from sapping watts that would otherwise be going into forward propulsion.

I'll stick to my rock solid Ksyriums then.

There are many shades of grey.. some people like to place their pads 1 mm away from the rim... in which case any rim will flex enough to get some rubbing, including your alleged rock solid Ksyrium. Some people place them 3 mm away and never experience rub, even with butter rims... The OP also made clear it only happened up Yorks hill... are you familiar with the climb? It's 1 in 5 and not particularly well surfaced which increases the effort required to go up it.
Some people also carry a lot of crap and crud on their pads, making the chance of brake rubbing even greater... that said, I would have built the rear with Sapim Race instead of the Laser used on the NDS