Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > General Motorcycles only > Mountain bike problem

[rockhopper]

Right then, got an annoying problem with my Specialized S works M4 hardtail.

Its an oldish frame, about 2000 i think so it didnt have disk mounts. I'm running hope disks with their own adapter on the back, hope sport hubs and an XT skewer on the back. The problem is that no matter how tight i do up the skewer the back wheel moves in the drop outs if i put a lot of weight on the pedals. Sometimes it will move enough to touch the chain stay.

Tonight though it's moved just enough to make the disk rub the pads slightly.

Its really starting to annoy me.

Anyone got any ideas?

Should i start saving up for a full suspension bike?

[Ian Harris]

H'mmm, I'm sure that there will be someone along soon who's better qualified than me to comment on mountain bikes , as I'm an old "roadie", but one common problem is adusting the axle so its too close to the end of the dropout. This means that the clamping surface of the skewer is not fully suported, so when you apply torque, it is able to pull past the end of the dropout, so you should always have some of the dropout visible past the skewer (blimey, that didn't make much sense even to me )

If you are a bit of a power house, the answer is to get a frame with vertical dropouts...this means there is no wheel-base adjustment, but you cannot force the spindle to move, as the only way it can go is vertically down.

At the end of the day, Q/R back wheels pulling out of alignment is a fact of life if for the really strong bloke, that's one reason why you don't get Q/Rs on Track bikes...the force that some of those "incredible hulk"sprinters apply is pretty bl00dy scary.

Anyway, if its not the "spindle too close to the end of the dropouts" problem, you'd better wait till someone who knows ehat they're talking about comes along....is it Gizmo that's the mountain bike guru?

[Gizmo]

Seen it before with hard anodised drop outs and certain QR skewers, the skewer should have knurled bits which grip the paint on frame which an XT should have, if the frame is hard anodised or the drop out design means the skewer clamps to dropout not frame that can cause it. We went to a harder dropout on one model because people complained the hanger bent too easily, resulted in a few riders having same problem, put power on and wheel pulls over. it can also be a difference in dropout dimensions, they are usually about 10mm +.2 but some are bigger than that, occasionally you'll get a Hope hub axle that doesn't seat exactly. I'd be surprised if an S works bike was like that though.

If it wasn't designed for discs and you run that adaptor that might also stop skewer clamping up, not sure though as its a long time since I saw one. AIR there is a different skewer cap on it which recesses into the arm, not sure what the arm fastens against on frame though. might be worth giving Hope a call, their customer service is excellent.

[rockhopper]

Hi guys, Yep Gizmo, you are right, the XT skewer has a different end on it to suit the hope disk adapter. The end is smooth on the face which touches the dropout. I tried a star washer last night but it didnt help. I'll get in touch with Hope. Its such a long time since i built the bike that i can't remember all the details!

Ian, the slot in the dropout is angled slightly forward which doesnt help matters. I noticed the other week when i looked in the local bike shop that most of the current mountain bikes had vertical slots. The wheel is always as far into the drop out as it can go, there is no need for wheelbase adjustment as such becasue the deraileur will take up the chain slack.

Is there an alternative to running the disk adapter? Is it possible to get a disk mount welded on?

[Gizmo]

Originally posted by rockhopper

Is there an alternative to running the disk adapter? Is it possible to get a disk mount welded on?

No other way except welding, can't recall what the M4 was made out of, I think I know which company made them , its not the metal matrix version is it?? if not it'll probably be 6066 or a similar exotic 6 series alloy, they spent a bit of time working on 6 series stuff to improve it, if you get tabs welded on frame will need re heat treating, it also needs jigs to align the dropouts exactly and a repaint and decals, not an easy task and we never do it, it would end up more expensive than a new frame.

Is the frame OK with a v brake fitted??

[desmojen]

Start saving for a new bike!
Or, if you have a lot of nice bits on that one, get a new frame. I just did that with my bike. I had a Giant MCM980 full susser for 6 years and the wheels started to get a bit bent and then one of the seals went. I decided to use that as a perfect excuse to get a new wheelset and upgrade to discs at the same time.
So off I went and bought a set of disc wheels and disc brakes with integrated shift levers, only to find that there's no way that bike's ever gonna have discs on it because the disc touches the chainstay! Oops!
So there I am with a load of bits I can't use.
Answer, buy a new frame. I decided on a Giant Trance frame and then discovered that the Trance4 bike was only another £100, so I've bought that, swapped all the bits over and now have a nice disc brake full susser and an old one for sale on ebay with nice new wheels and forks!
What a polava!
http://cgi.ebay.co.uk/ws/eBayISAPI.d...MESE%3AIT&rd=1

P.S. This is not a shameless advert, just thought you might be interested in the story

[rockhopper]

Its a metal matrix American built frame. I didn't think welding a mount on was really an option!

Its a long time ago but yes, i think it was okay with V brakes, but i'd rather not go back to them after having disks.

I've emailed Hope this morning to see if they come up with anything.

[rockhopper]

My problem is that i'f i'm going down the new bike route then i want it to my spec so it'd have to be an S works full suspension frame (£1200) plus Pace forks (£400) with the spangley new Hope brakes and then all of a sudden I've spent well over £2K!

I don't think she'd ever speak to me again if i did that.

[Gizmo]

Originally posted by rockhopper
Its a metal matrix American built frame. I didn't think welding a mount on was really an option!

Its a long time ago but yes, i think it was okay with V brakes, but i'd rather not go back to them after having disks.

I've emailed Hope this morning to see if they come up with anything.

the metal matrix an be welded but it'll be even more complex and might involve a trip back to the maker in the US Its not a viable option.

So, if its OK with v brakes it has to be the Hope mount thats letting it slide. I don't think its possible to run a 10mm bolt thro rear axle because of the arm so theres no way of really tightening it up other than a QR, it has to be the arm/frame interface where its moving Personally I'd pick up the good old dog and bone and talk to Hope, they like us are a very small company who are manufacturers first and foremost and aren't really set up to handle customers, they expect their dealers to do that. Email is a pain in the ar'e, it takes forever to sort a problem which can be delat with in minutes on the phone. 01282 851200 if I recall correctly

[Gizmo]

Originally posted by rockhopper
My problem is that i'f i'm going down the new bike route then i want it to my spec so it'd have to be an S works full suspension frame (£1200) plus Pace forks (£400) with the spangley new Hope brakes and then all of a sudden I've spent well over £2K!

I don't think she'd ever speak to me again if i did that.

I've got a nice ex demo 2005 Five sat here my own personal use bike, XT dual control, discs, Nixon elite forks or Manitou Minutes or RS Pikes depending upon what you prefer , got my new bike on its way, 06 Five, Fox 36's, DHX air rear shock, mmmmmm .......