|
Author |
Message |
stinkwheel |
This post is not being displayed .
|
stinkwheel Bovine Proctologist
Joined: 12 Jul 2004 Karma :
|
Posted: 21:18 - 21 Feb 2013 Post subject: Deliberately bending a bicycle frame? |
|
|
I've decided that I can no longer cope with the cyclocross tyres I've been using on my wholly inappropriate mountain bike. The pressure you need in them to prevent pinch-flats means it's painful doing any speed over hard ground and grip on wet stones is non-existant.
So. "proper" MTB tyres it is. Unfortunately, they JUST foul the chainstays. If the wheel was entirely true and dead-centre, they wouldn't touch at all but I'd give it 5 minutes befoe that's no longer the case with someone my weight.
Can't get narrower tyres, these ARE the narrow ones. I could shave bits off some of the knobs but this seems self-defeating and the tyres are worth more than the bike.
What would fix it is if I could put a bit of a bend in the chainstays where the tyre runs past. A few mm is all it would need. The question is how? It's a steel frame.
I thought about bolting an old hub between the dropouts to keep them in place and jacking the chainstays apart but my car jack is too wide to fit in the gap. Maybe I could even lever them apart with a fencepost and a bit of brute-force?
Anyway. Also photowhoring. Note 29" MTB tyres on 700c road wheels.
https://i48.photobucket.com/albums/f216/stinkwheel/CIMG0873_zpsc3b17a98.jpg
https://i48.photobucket.com/albums/f216/stinkwheel/CIMG0874_zps591014f5.jpg
https://i48.photobucket.com/albums/f216/stinkwheel/CIMG0876_zps86d31fbb.jpg
Anyone know if that gussett plate bewteen the chainstays you'd attach a mudguard or calliper brake to is structurally essential? ____________________ “Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles. |
|
Back to top |
|
You must be logged in to rate posts |
|
|
The Shaggy D.A. |
This post is not being displayed .
|
The Shaggy D.A. Super Spammer
Joined: 12 Sep 2008 Karma :
|
Posted: 22:07 - 21 Feb 2013 Post subject: |
|
|
I'm wondering whether you could fashion a turnbuckle to use as a spreader, from a couple of bolts and some threaded tube, along the lines of one of these :-
https://www.ebay.co.uk/itm/Turnbuckle-/321074997250 ____________________ Chances are quite high you are not in my Monkeysphere, and I don't care about you. Don't take it personally.
Currently : Royal Enfield 350 Meteor
Previously : CB100N > CB250RS > XJ900F > GT550 > GPZ750R/1000RX > AJS M16 > R100RT > Bullet 500 > CB500 > LS650P > Bullet Electra X & YBR125 > Bullet 350 "Superstar" & YBR125 Custom > Royal Enfield Classic 500 Despatch Limited Edition (28 of 200) & CB Two-Fifty Nighthawk > ER5 |
|
Back to top |
|
You must be logged in to rate posts |
|
|
G |
This post is not being displayed .
|
G The Voice of Reason
Joined: 02 Feb 2002 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Pete. |
This post is not being displayed .
|
Pete. Super Spammer
Joined: 22 Aug 2006 Karma :
|
Posted: 22:28 - 21 Feb 2013 Post subject: |
|
|
I would not try spreading those tubes so close to that spreader plate. I would either remove the plate and re-weld after easing the tubes out or make a tool to crush the inside of the tubes in whilst preserving the outer wall. Another option is increase the wheelbase slightly by moving the rear wheel back. ____________________ a.k.a 'Geri'
132.9mph off and walked away. Gear is good, gear is good, gear is very very good |
|
Back to top |
|
You must be logged in to rate posts |
|
|
stinkwheel |
This post is not being displayed .
|
stinkwheel Bovine Proctologist
Joined: 12 Jul 2004 Karma :
|
Posted: 23:04 - 21 Feb 2013 Post subject: |
|
|
I've had another engineering type suggest flattening the inner wall of the tube. Presumably this makes structural sense.
Thinking along those lines. If I were to remove that plate, heat things up nice and toasty then slowly hammer a wedge in there from the top then the bottom (I think I've got some oak about somewhere), it ought to both flatten and slightly spread the area in question without disrupting the shape of the outer part of the tube.
I'm not even sure how structural that plate is. Might even be brazed on.
Mind you. I just found an article on Sheldon Browns website where he widens the distance between the dropouts on bicycle frames using a big lump of 2x4 braced against the seatpost. Perhaps I'm being too technical. If I do a similar thing but with a hub bolted in place...
https://sheldonbrown.com/images/frame-spacing-l.jpg ____________________ “Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles. |
|
Back to top |
|
You must be logged in to rate posts |
|
|
G |
This post is not being displayed .
|
G The Voice of Reason
Joined: 02 Feb 2002 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Pete. |
This post is not being displayed .
|
Pete. Super Spammer
Joined: 22 Aug 2006 Karma :
|
Posted: 23:09 - 21 Feb 2013 Post subject: |
|
|
My experience with such things is that one side will usually give first, and the weakening that initial give creates causes that side to deform more. I would look for a more controlled method. ____________________ a.k.a 'Geri'
132.9mph off and walked away. Gear is good, gear is good, gear is very very good |
|
Back to top |
|
You must be logged in to rate posts |
|
|
smegballs |
This post is not being displayed .
|
smegballs World Chat Champion
Joined: 28 Oct 2007 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
stinkwheel |
This post is not being displayed .
|
stinkwheel Bovine Proctologist
Joined: 12 Jul 2004 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
haroman666 |
This post is not being displayed .
|
haroman666 World Chat Champion
Joined: 17 Sep 2008 Karma :
|
|
Back to top |
|
You must be logged in to rate posts |
|
|
Old Thread Alert!
The last post was made 11 years, 35 days ago. Instead of replying here, would creating a new thread be more useful? |
|
|
|