[Closed] Rear wheel flex. .. How to stop ?

Think this one has come up before and this link got shared by someone...

http://www.slowtwitch.com/Tech/Debunking_Wheel_Stiffness_3449.html

Not a quick answer and it's pretty road focussed, but nice and geeky... 🙂

is it built differently to the way it was before, or same rim, spoke setup ?

Take it back to the builder.

I agree with fasthaggis. If everything else is the same, the build is the problem.

Do you have much tyre clearance? Is it genuinely wheel movement or could the tyre be rolling on the rim? How big are the tyres you’re running? Any movement in the dropouts or the hub bearings? Can you flex the wheel by hand?

Would a change to straight spokes help

Well you'd need a new hub to do that so a bit drastic

or a stronger rim ?

If built correctly

Almost like the tyre pressure is low.

Is it?

Was it flexy before the rebuild?

What do you weigh? HT or FS?

get a pair of wheels built to suit your size, and type of riding you do.

I don't know how flexy it was before as I bought the wheels secondhand from here and found the hub cracked straight away.

I meant would plain guage spokes be stronger than double butted.

Wheel is built fine. The builder is quite well known in the area for his wheel builds. All spokes are correct tension etc.

I can flex the wheel a bit by hand. The tyre is a 2.3 with plenty of clearance.

Sorry forgot to add....

Full suss Codeine with maxle rear end.

I am 110kg

Is it definitely the wheel flexing? Not the frame, or the hub is not right?

Also is the tyre on straight? Had tyre rub the frame before because they just weren't seated right and had excess wobble. The wheel was perfectly true though. Though if it feels flexy I guess it's less likely, unless it's not seated right at all and thus squirming a lot.

What was the builders opinion,did they suggest anything?

Edited: because I'm an idiot.

You say the spokes are the correct tension, how do you *know*...?

Which wtb rim? ST? Frequency? Kom?

I23 rim.

Wheel builder suggested plain guage spokes.

Wheel built and tested with a spoke tension meter.

Try another wheel in there, I reckon there is more chance of an on one flexing than that wheel, and tyre deformation is a good shout too.

Sorry,I should have added.

Have you spoken to the builder about the problem since the initial build?
They would be my first contact if it's not right,or rubbing the frame due to flex.

i23 is the width, wtb make a few different rims with that width / suffix.

(For example, the Kom rims seem very light for an aluminium 29er rim. Light, stiff, aluminium, pick 2)

Which spokes? Dt comp have a 1.8mm diameter, dt race (?) are 1.5...

I think the spokes are 1.8 - 1.5 - 1.8.

I reused the original spokes.

Maybe some plain guage spokes would help.

The wheel builder did say they were more of an xc build spoke and that I may get some flex too.

Edit : rim is wtb st i23.

I'm not convinced the frame is flexing either as it's built like a tank.

1.8 - 1.5 - 1.8 and 110kg will make the wheel flex under hard load so I'd suggest a heavier guage spoke, like a Sapim race, or perhaps a diet.

17+ stone? I think there lies your problem.

Plenty of heavier riders on here than me mate.

Yes, but you're on a relatively narrow rim with quite thin spokes.
I only meant that your weight's only an issue in respect to that 😉

So should I try a spoke change or would a rim and spoke change be better ?

If so what rims and spokes ??

I think you should speak to the builder and get some advice from them.

Wheel built and tested with a spoke tension meter.

But do they *feel* tight now? (Squeeze test)

I'll bet that they've gone a bit slack after riding the wheel.

I'm not convinced the frame is flexing either as it's built like a tank.

Just because something looks 'clydebuilt' does not mean it is stiff.

Try a different wheel in there, either that, or just do as you usually do - come on here, ask a question, get lots of helpful advice and ignore it, as it's not what you want to hear.

1.8 1.5 1.8, what spoke is this, revolutions? That guage would be a race day weight weeinie spoke surely.
2.0/1.8/2.0 competitions would be good and DT rate a 28hole xm spline wheelset to 120kg. 32h sees you plenty strong for 110kg. I have a similar weight pal rinding my old 32h xm471/204/competition build and its the first set of wheels that he's ever found to be stiff.

I weigh 35kg less than you and I only use 1.8/1.5 spokes on my lightweight race wheels.

Wouldn't dream of anything that light on a general trail bike even for me. I hope it's not a low spoke count wheel too...

Go back to the builder and ask for advice on a build for your weight and riding. There's nothing wrong with being heavy, but there is something wrong with using inappropriate components for your weight.

Thanks all.

Would the rim be strong enough then do you think ?

I'm sure it's a 32 hole rim and hub.

The wheel builder did comment on the spokes when he was building it as they were the spokes from the previous build.

I will go and ask his advice and see what he says.

Cheers.

So should I try a spoke change or would a rim and spoke change be better ?

If so what rims and spokes ??

For a nice solid build something like a Stans Flow or DT Swiss EX511 with 2/1.8/2 DB spokes.

I had similar problems with my first 29er (a hardtail). I'm about 86kg with full winter kit on, and tried some Pro2 + Crest wheels on there. Trail centre reds were mostly OK, but on rougher natural rides it felt like the rear axle was loose - it wasn't, it was the rim flexing. Swapped to Arch EX's with same hubs and spoke type, and that solved the problem.

If you want a decent quality stiff rim, I can recommend the latest 25 & 30mm internal width DT stuff - have some of the 30's on my long travel 29 and they are brilliant. No flex, but not harsh with it either.

Cheers.

What models are the decent dt rims I need to look at then.

To my the flex felt like the tyre was rolling on the rim. I kept checking as I thought it was going down but it wasn't.

Tyre is a 2.3 ground control set up tubeless.

I had this and had the wheel rebuilt twice.

It turned out to be the one of the pivots on the rear Tri.

Whoops.

ex471 25mm 530g
xm481 30mm 525g
xm421 25mm 465g

I'd probably go the 481.

Ooof they aren't cheap are they.

How would an st i29 compare to the i23 that I have ?

CRC have them on offer ?

is it a pro/shop who are doing build ? will they be happy building bits you buy online ?

I have i29 Asyms on the Bronson, Don't think I'd buy them again, they are nowhere near as robust as my previous DT swiss were, XM1501's.

They ding very easily.

Wheel builder sounds a bit daft TBH. He/she shouldn't have built the wheel up for you with those spokes in the first place.

Nah I can't blame the builder as I said use the original spokes to keep the cost down.

Hindsight and all that .....

I can't afford to spend £70 odd quid per rim to be honest. So what's my options.

I build all my wheels with plain guage 2.0 spokes and have no issues with wheels flex

So what's my options.

A new hobby, I'd suggest. I can't recall a bike you've ever been happy with.

Nope mate I'm quite happy with this as it stands.

Apart from the wheel obvs.

what's my options.

Buy a wheelset from Merlin that meets your weight and riding requirements, sell the ones you have