Wheel bending to left under braking, won't align back again

[krzychoniusz]

I recently upgraded front fork to rockshox recon so I can swap the front disc brake from 160mm to 203mm on my 29er. Since then, under braking the wheel pulls heavily to the left, so much that it rubs the forks. Interestingly, the wheel does not align back when braking is over, but when I take it out of the forks and put back in it tends to sit straight again. I tried replacing wheel (thought might be the hub, or misaligned wheel) but the issue still occurs. Brought it to a local bike shop, but they had a hard time figuring it out. Hub was serviced and adjusted (centered), spoke tension checked (all fine). They believe it could either be QR axel skewer that is not strong enought to hold the wheel in place, or massive wheel flex due to inadequate rim width. I tried 3 different skewers but no luck, so temporarily ruled that out. I haven't upgraded the rim yet as I would have thought if it's indeed the rim, the problem would either be permanent damage (rim gets bent) but if so then taking wheel out and putting back in the forks would not fix the issue is it does right now; or if it was just a massive braking flex then it should align back to centre again once braking is over. Any ideas what else could it be? I thought the fork might be damaged/misaligned (bought second hand) but the mechanic from the bike store says that doesn't seem to be the case.

 

[Deleted member 25121]

First of all let me say that I've never come across this.
I wonder if there's a problem with the left fork flicking backwards under heavy braking and only returning after pressure from the QR skewer is released, if you see what I mean. The mechanic many have only looked at the forks when they were back in their normal position.
Could be tricky to diagnose, try looking down from the handlebar onto the ends of the skewer when the wheel is in the good position (should be alignment) and again when its in the bad position (left hand skewer end too far back??)

 

[awol]

Grab hold of the top of the wheel and try pushing/pulling it left/right (from fork to fork) to see if there is any play in the bearings.
With it in the good position stand with your bike and your handlebars turned about 60degrees pointing right, tightly apply the front brake and try rocking the bike forwards/backwards so you are pushing against the wheel side-on, and can you see any movement from anywhere.

 

[vfr400]

It sounds like the bushes in the forks are worn to me. Are they new or used?

 

[KirstinS]

I had a similar issue with cheap ebay titanium qr skewers

Went back to standard but decent shimnao skewers and the issue went away

Not the same issue exactly but worth a mention I think

 

[Andy-Mat]

Grab hold of the top of the wheel and try pushing/pulling it left/right (from fork to fork) to see if there is any play in the bearings.
With it in the good position stand with your bike and your handlebars turned about 60degrees pointing right, tightly apply the front brake and try rocking the bike forwards/backwards so you are pushing against the wheel side-on, and can you see any movement from anywhere.

I think that is really good and practical advice to start off with.
I personally have never heard or seen such problems with regard to wheels/brakes, so I am following this topic, hoping to learn more - just in case!!
regards and Many Thanks
Andy