New Carbon Wheelset - Imbalance ?

rickeverett

Just got my first set of Carbon wheels (VENN REV 35 TCC). When setting them up on the bike (bike on a stand) I noticed at high rpm when turning the rear wheel the bike would bounce / wobble badly. The front wheel when I lift off the ground also tugs up and down when spinning. They both settle at the valve end with or without tube and trye.

I put it down to poor tyre fit or valve length so took it all off back to the naked wheel - both still tug / bounce.

Is this normal for Carbons ????? - Seen a video with a ££££ Zipp set do the same ! ?

On a test ride and at high downhill speed I felt nothing at all. In fact they felt fantastic so it doesn't effect the ride as far as I can tell yet.

What can I do / or should I do anything at all ?

cougie

If it doesn't matter when your weight is on the bike then I'd not worry.

imposter2.0

No need to do anything. You said yourself that they ride fine - so what they do on the stand is irrelevant.

haydenm

It might be just that they are so light any slight difference is more pronounced, as it's a bigger proportion of the over all weight. I was thinking the weight of the valves but you say it does it without them, but if they settle there anyway then there is some sort of insert or reinforcement there. I'd just ignore it unless they are out of true or round, which would be a poor build, should be an easy fix by someone who knows what they are doing

Nice wheels!

Vino'sGhost

rickeverett wrote:

Just got my first set of Carbon wheels (VENN REV 35 TCC). When setting them up on the bike (bike on a stand) I noticed at high rpm when turning the rear wheel the bike would bounce / wobble badly. The front wheel when I lift off the ground also tugs up and down when spinning. They both settle at the valve end with or without tube and trye.

I put it down to poor tyre fit or valve length so took it all off back to the naked wheel - both still tug / bounce.

Is this normal for Carbons ????? - Seen a video with a ££££ Zipp set do the same ! ?

On a test ride and at high downhill speed I felt nothing at all. In fact they felt fantastic so it doesn't effect the ride as far as I can tell yet.

What can I do / or should I do anything at all ?

Congratulations on the new wheels! and now the bad news. These wheels sound like theyre suffering from rotating unbalance which is caused when the mass of the wheel surrounding the hub is not even, it creates a wobble which when the wheel isn't in load i.e. youre not sitting on it can be pronounced.

Uneven mass can be caused by something as simple as a little more material around drillings such as the valve holes, theres more material there to beef up the area where a hole has been drilled or moulded so nothing untoward there.

Under high revolution conditions on a stand no problem but underload it causes the spokes to be loaded and then unloaded in an uneven way, adding stress to the wheel and they're almost certain to become untrue as spokes work loose. Furthermore there's likely to be a catastrophic failure in conditions where there is sustained high speed. (think coming down a hill).

I recommend you send the wheels to me and Ill test them for a few years

rickeverett

HaydenM wrote:

It might be just that they are so light any slight difference is more pronounced, as it's a bigger proportion of the over all weight. I was thinking the weight of the valves but you say it does it without them, but if they settle there anyway then there is some sort of insert or reinforcement there. I'd just ignore it unless they are out of true or round, which would be a poor build, should be an easy fix by someone who knows what they are doing

Nice wheels!

The wheels are very true and came with a hand written check sheet which was nice. They do look ever so slightly off in terms of round and move about 0.5mm or so.

rickeverett

Vino'sGhost wrote:

rickeverett wrote:

Just got my first set of Carbon wheels (VENN REV 35 TCC). When setting them up on the bike (bike on a stand) I noticed at high rpm when turning the rear wheel the bike would bounce / wobble badly. The front wheel when I lift off the ground also tugs up and down when spinning. They both settle at the valve end with or without tube and trye.

I put it down to poor tyre fit or valve length so took it all off back to the naked wheel - both still tug / bounce.

Is this normal for Carbons ????? - Seen a video with a ££££ Zipp set do the same ! ?

On a test ride and at high downhill speed I felt nothing at all. In fact they felt fantastic so it doesn't effect the ride as far as I can tell yet.

What can I do / or should I do anything at all ?

Congratulations on the new wheels! and now the bad news. These wheels sound like theyre suffering from rotating unbalance which is caused when the mass of the wheel surrounding the hub is not even, it creates a wobble which when the wheel isn't in load i.e. youre not sitting on it can be pronounced.

Uneven mass can be caused by something as simple as a little more material around drillings such as the valve holes, theres more material there to beef up the area where a hole has been drilled or moulded so nothing untoward there.

Under high revolution conditions on a stand no problem but underload it causes the spokes to be loaded and then unloaded in an uneven way, adding stress to the wheel and they're almost certain to become untrue as spokes work loose. Furthermore there's likely to be a catastrophic failure in conditions where there is sustained high speed. (think coming down a hill).

I recommend you send the wheels to me and Ill test them for a few years

I hope you were joking I the last bit.

Matthewfalle

rickeverett wrote:

Vino'sGhost wrote:

rickeverett wrote:

Just got my first set of Carbon wheels (VENN REV 35 TCC). When setting them up on the bike (bike on a stand) I noticed at high rpm when turning the rear wheel the bike would bounce / wobble badly. The front wheel when I lift off the ground also tugs up and down when spinning. They both settle at the valve end with or without tube and trye.

I put it down to poor tyre fit or valve length so took it all off back to the naked wheel - both still tug / bounce.

Is this normal for Carbons ????? - Seen a video with a ££££ Zipp set do the same ! ?

On a test ride and at high downhill speed I felt nothing at all. In fact they felt fantastic so it doesn't effect the ride as far as I can tell yet.

What can I do / or should I do anything at all ?

Congratulations on the new wheels! and now the bad news. These wheels sound like theyre suffering from rotating unbalance which is caused when the mass of the wheel surrounding the hub is not even, it creates a wobble which when the wheel isn't in load i.e. youre not sitting on it can be pronounced.

Uneven mass can be caused by something as simple as a little more material around drillings such as the valve holes, theres more material there to beef up the area where a hole has been drilled or moulded so nothing untoward there.

Under high revolution conditions on a stand no problem but underload it causes the spokes to be loaded and then unloaded in an uneven way, adding stress to the wheel and they're almost certain to become untrue as spokes work loose. Furthermore there's likely to be a catastrophic failure in conditions where there is sustained high speed. (think coming down a hill).

I recommend you send the wheels to me and Ill test them for a few years

I hope you were joking I the last bit.

why should he be joking?

with this being a vital safety matter i'd take him up on it straight away.

Vino'sGhost

Matthewfalle wrote:

rickeverett wrote:

Vino'sGhost wrote:

rickeverett wrote:

Just got my first set of Carbon wheels (VENN REV 35 TCC). When setting them up on the bike (bike on a stand) I noticed at high rpm when turning the rear wheel the bike would bounce / wobble badly. The front wheel when I lift off the ground also tugs up and down when spinning. They both settle at the valve end with or without tube and trye.

I put it down to poor tyre fit or valve length so took it all off back to the naked wheel - both still tug / bounce.

Is this normal for Carbons ????? - Seen a video with a ££££ Zipp set do the same ! ?

On a test ride and at high downhill speed I felt nothing at all. In fact they felt fantastic so it doesn't effect the ride as far as I can tell yet.

What can I do / or should I do anything at all ?

Congratulations on the new wheels! and now the bad news. These wheels sound like theyre suffering from rotating unbalance which is caused when the mass of the wheel surrounding the hub is not even, it creates a wobble which when the wheel isn't in load i.e. youre not sitting on it can be pronounced.

Uneven mass can be caused by something as simple as a little more material around drillings such as the valve holes, theres more material there to beef up the area where a hole has been drilled or moulded so nothing untoward there.

Under high revolution conditions on a stand no problem but underload it causes the spokes to be loaded and then unloaded in an uneven way, adding stress to the wheel and they're almost certain to become untrue as spokes work loose. Furthermore there's likely to be a catastrophic failure in conditions where there is sustained high speed. (think coming down a hill).

I recommend you send the wheels to me and Ill test them for a few years

I hope you were joking I the last bit.

why should he be joking?

with this being a vital safety matter i'd take him up on it straight away.

Yes it's imperative that they're tested under real world conditions to identify any issues in performance, longevity and ease of maintenance. I'm prepared to do this for you at no charge. All i ask is that you cover the cost of postage getting them to me and please remember to send any brake pads that came with the wheels.

At the end of a prolonged test i will issue a certificate of satisfaction;
or not, if they've collapsed on a descent.

shortfall

Be interested to hear a real world review of these wheels. They're very competitively priced when compared to pretty much anything else outside of Chinese imports. Cycling Weekly rated them highly.

Vino'sGhost

seee its not only you that wants me to test them, the forum needs to know too.

if you send them special delivery ill get started this weekend.

rickeverett

Vino'sGhost wrote:

seee its not only you that wants me to test them, the forum needs to know too.

if you send them special delivery ill get started this weekend.

Yeah yeah ok ok... :roll: :P


First ride on them for those who would like to know was fantastic. They spin up quick and roll really well but the most noticeable thing was comfort compared with my same weight (1.4kg) ally set. This combined with a noticeable speed improvement does tie in line with the Cycling Weekly review.

And yes. The weight is much less than the quoted too!

Build quality is top. Zero complaints. ... Apart from the imbalance when in the stand.

StillGoing

If you want to solve it, buy some golf stick on weight strips. Find the opposite part of the circumference from the heavy spot and apply the strips until you even the weight out. Cover them with black tape to mask the appearance. Did it with my Mavics and solved the vibration.

rickeverett

I have purchased some lead weight strips in an attempt to balance the wobble. With true and tube it's 12g front and 18g rear.

I intend to remove the rim tape and put the weights in the rim and recover with tape as they are only 1cmx5cm X 1mm. Good idea ? I would think the tube will just mould around the lump and the tyre is not affected.

cougie

Why bother ? It's only apparent with no weight on the bike.

The bike isn't going to ride itself is it ?

shortfall

rickeverett wrote:

Vino'sGhost wrote:

seee its not only you that wants me to test them, the forum needs to know too.

if you send them special delivery ill get started this weekend.

Yeah yeah ok ok... :roll: :P


First ride on them for those who would like to know was fantastic. They spin up quick and roll really well but the most noticeable thing was comfort compared with my same weight (1.4kg) ally set. This combined with a noticeable speed improvement does tie in line with the Cycling Weekly review.

And yes. The weight is much less than the quoted too!

Build quality is top. Zero complaints. ... Apart from the imbalance when in the stand.

How is the braking? Seen a couple of customer reviews on PBK saying it was dogsh1t. What pads. (blocks) are you using?

rickeverett

Shortfall wrote:

rickeverett wrote:

Vino'sGhost wrote:

seee its not only you that wants me to test them, the forum needs to know too.

if you send them special delivery ill get started this weekend.

Yeah yeah ok ok... :roll: :P


First ride on them for those who would like to know was fantastic. They spin up quick and roll really well but the most noticeable thing was comfort compared with my same weight (1.4kg) ally set. This combined with a noticeable speed improvement does tie in line with the Cycling Weekly review.

And yes. The weight is much less than the quoted too!

Build quality is top. Zero complaints. ... Apart from the imbalance when in the stand.

How is the braking? Seen a couple of customer reviews on PBK saying it was dogsh1t. What pads. (blocks) are you using?

Pads are currently the ones that came with the wheels so can only go off that. They aren't Swiss top carbons for example.

So far I would say different. They don't bite the same like my Swiss top on ally rims but they certainly stop you. I would probably need more time to bed them in first but wouldn't say they are dogsh1t.

sungod

rickeverett wrote:

I have purchased some lead weight strips in an attempt to balance the wobble. With true and tube it's 12g front and 18g rear.

I intend to remove the rim tape and put the weights in the rim and recover with tape as they are only 1cmx5cm X 1mm. Good idea ? I would think the tube will just mould around the lump and the tyre is not affected.

no, it's not a good idea, it's a bad idea, all you're doing is making your wallet lighter and your wheels heavier

the trivial imbalance you describe can be probably be found on the vast majority of wheels, it will make no difference when riding

StillGoing

rickeverett wrote:

I have purchased some lead weight strips in an attempt to balance the wobble. With true and tube it's 12g front and 18g rear.

I intend to remove the rim tape and put the weights in the rim and recover with tape as they are only 1cmx5cm X 1mm. Good idea ? I would think the tube will just mould around the lump and the tyre is not affected.

https://youtu.be/dcgiUcbS64c

cougie

Is there a summary of that 14 Mon video ?

sandyballs

I will sum it up:

Man has wobbly wheel, adds some sticky weights by trial and error, wheel doesn’t wobble.

My Zipps do exactly the same when the bike is on a stand, cannot feel a thing on the road without ever worrying about it or adding unnecessary weight to what is supposed to be a lightweight wheel set.

cougie

Ta.

MiddleRinger

cougie wrote:

Is there a summary of that 14 Mon video ?

Yep. Shane's summary is basically; "Would you do it if you're going for an hour record on a smooth velodrome. Absolutely you would."

Marginal gains and all that. If you're at the pointy end of the results board on the domestic time trialling scene it's probably worth it. For the average punter, probably makes no difference at all.

StillGoing

I did it as on the rollers, the vibration was noticeable. Add the weights to balance the wheels and the vibration has gone.