The swing arm on my stumpjumper is really rather flexy, my tyres rub it to the point that I have to armour it with zip ties to protect the frame.

It is a standard 9x135mm dropout and I have hope hubs so I was thinking about a bolt up axle kit. Would this actually make any difference?

Are there any better/other ways to reduce the flex?

If its a Pro2 hub, then you can convert it to 9mmm bolt thru and get a QR axle thing which will stiffen it a bit.

Check your spoke tension?

Spesh demo 8 bolt up rear axel kit worked well on sx trails. Downside is an 8mm key and a spanner to get the wheel out

Check your spoke tension?

Ditto. Can’t beleive anyojne would think it had anythng to do with the axle. 🙄

Spoke tension seems OK, they are flow ex rims so not the stiffest but they still rub on much stronger rims.

Surely bolting the axle up good and tight would brace the swingarm together at its extremity therefore giving it less opportunity to twist and flex. Isn’t that the whole idea behind through axles? I can’t see how this is any different.

There will be far more flex in the rim and spokes than you could ever feel thought the ale, unless it weas made of rubber. And the swingarm wil be stiffer than yuor wheel.

Isn’t that the whole idea behind through axles?

The stiffer the axle, the more your swingarm would fles. Think bout it>

Regarding checking spoke tension..what’s required? On my older sets of wheels I used to just go round each spoke and nip it up quarter of a turn, then repeat.
I’ve got rub marks on my anthems rear triangle, I just assumed it was down to tyre squirm from running lower pressures with tubeless.

Wheel stiffness does not vary significantly with spoke tension unless a spoke becomes totally slack.
here

Definitely worth getting the 10mm axle conversion for the hub and one of Superstar’s 10mm QRs.

Made a big improvement to the rear on my old QR Mondraker.

(Warning: This is posted from actual experience rather than armchair theorising)

chakaping – Member
Definitely worth getting the 10mm axle conversion for the hub and one of Superstar’s 10mm QRs.

Made a big improvement to the rear on my old QR Mondraker.

(Warning: This is posted from actual experience rather than armchair theorising)

Second that, based on using one on my old Heckler. Proper noticable difference when compared to a standard 5mm QR.

What size tyres are you using back there? Are you sure it’s not a low pressure big ass tyre that’s flexing / rolling when cornering that’s doing it? What clearance between the tyre and the frame?

I’ve had Superstar and DT thrubolt QR things, they do actually stiffen the back end up, even when actually really riding, in real life.

Bearings? Maybe the main pivot and hub bearings are on the fritz?

Another vote for a Superstar 10mm axle.

Had a problem with the rear wheel of my Marin rubbing the chainstays and was told by two LBS’s that there was nothing wrong with the wheel and that it was typical of Marin’s and because of the evolution of how people ride!?

A new wheel and a 10mm axle saw a week of riding in Morzine/Chatel/Les Gets pass without any wheel rubbing, could have been the wheel, could have been the axle, who knows.

My old Kona is prone to this depending on what tyre is fitted, not all 2.3s are the same height/width.
I fitted a tftuned top shock mount kit which seems to have stiffened the rear.
http://www.tftunedshox.com/info/mount_kits_bushings.aspx
New wheels built super tight by BigAl @ Wheelcraft also contributed to the lack of sideways/seat stay rub 😆

I was thinking pivot bearings.

However, I converted the wife’s fsr to a Hadley 10mm bolt through rear. I think it’s improved things but she’s not really noticed. She comes from the “just get on a pedal” school of thought.

Running big ass tyres though – 2.35 Rock Razor on the rear which is pretty huge so there’s not much clearance.

I can understand the tyre giving at the contact patch, but would it distort all the way up to the seat stays?

I_Ache – what you want is an Endur Evo frame… 😆

Well there is the large tyre thing yes but they are great tyres.

What frame for a Rock Razor?

I just spoke to Specialized UK and they will sell me a carbon rear end but its £400! I think I would be better off putting that towards a new frame. The bloke did say that a bolt up rear end would add a lot of stiffness so for only £30 or so I think I will go for that for the time being at least.