Dahon Curve D3 Setup help
I've just purchased a Dahon Curve D3 over the internet which i'm chuffed to bits with but i have had a few problems with it 'out of the box'.
The first thing i noticed were 3 paint chips which i've touched in with red nail varnish of all things! It's covered the chips very well but i don't know if it will last- anyone else tried this before?
Secondly, the rear of the front mudguard was rubbing against the tyre which was easy enough to fix by taking it off and tweaking the metal stays a little bit.
Thirdly and most worryingly, after riding just a couple of miles, i've noticed that the chain is rubbing against the frame and has already worn through the paint. Obviously that isn't right and needs sorting out before i ride it again or it will wear a groove in the frame. Has anybody else come across this before and know how to fix it? The chain is taught and it's alignment look to be straight but having no experience with bicycle mechanics before, i don't know what else to check?
Many thanks in advance,
Had you bought your Curve from a Local Bike Shop, then you could have taken it back there, but it sounds as though you are on your own here.
If the chain really is taught and the rear wheel central in the frame, then the chain should not rub on the frame. However, it is difficult to get the chain to the correct tension on the Curve after it's initial stretch from new. You can buy chain adjusters which will hold the wheel firmly, and these were metioned in a previous post on this forum.
The trouble seems to be that on re-tightening the wheel nuts after adjusting the chain the rear wheel has a tendancy to creep forward again, thus slackening the chain.
Try this :-
Loosen both wheel nuts. Note that drive side nut is hidden under the black plastic cover. Undo gear cable and pull of cover to access wheel nut. Keep locknut on gear cable close to adjuster so that you can maintain gear adjustment afterwards.
Pull wheel back to get chain tight (not too tight), but keep side of tyre in contact with inside of frame on the non-drive side.
Tighten the wheel nut on that side.
Now pull the wheel central in the frame and tighten the drive side wheel nut. The wheel should not slide forward again, since it is held by the tight wheel nut on the non-drive side.
Make sure that the chain is not too tight. If necessary go back and repeat the procedure with slightly more slack in the chain. Chains do not always stretch evenly and you may find that it is tighter in one position than another. Work to the slackest part and not the tightest.
Hope this cures your problem.
Thanks very much for the reply.
I've had another look at the bike but it's left me scratching my head somewhat.
The chain is indeed tight- i'm not sure how tight it's supposed to be but there's not very much up and down movement at all. To my eye, the wheel looks to be central in the frame but i don't know how alignment is measured correctly.
It looks like the chain is designed to run quite closely to the frame anyway and mine probably only needs moving across maybe 2-3mm. If the wheel is straight and the chain is tight, is there anything else that could be causing the problem?
It's a shame there are no decent local shops around here or as you say i could have taken it back to get sorted.
I think i'm going to pluck up the courage to try what you've suggested and hope i don't make things any worse. Just a couple of questions... how and where do i undo the gear cable from? Also, i can't figure out how to get to the drive side wheel nut once the black cover is off- does the other black plastic thing lift off once the gear cable is released?
Thanks again for the help.
It sounds like you have no local bike shop near your home? Or are you simply loathe to take it to a shop that will cost you some extra $$$$ for a tune-up? Whatever the case, you were probably led to believe that the Internet is a real virtual bargain bike shop where in reality, unless you purchased the bike from a store-be it bricks & motar or online- there it is checked out beforeyou received it, you are stuck with it. Do you have a friend, bike group, or even a shop nearby for you to consult? Or even better yet, try to contact the Internet store where you bought the bike. Perhaps they might take it back and fix it, offer to send you another bike, or even a refund if need be. You might be suprised at the response you get-in your favor I hope.
Did you perhaps get a manual for your hub? It will give you details on how to calibrate your hub when you reconnect things at the end. Internal geared hubs need to be recalibrated. I don't know the details of the SRAM T3 but the small cable chain and pulley over lock nut looks very similar to the Sturmey Archer XRF5, so I will try to advise, but hopefully someone with a T3 can chime in.
BTW this is the only manual I was able to find: ftp://126.96.36.199/BOOKLET/ENGLISH_SPECTRO.pdf
In any case internal hubs are pretty simple to calibrate.
To release the shifter cable from the little chain coming out of the hub, turn the barrel adjuster counter clockwise. It shouldn't take much force. There is probably a tiny lock nut, loosen it first. The tiny lock nut would be on the same thread as the barrel adjuster. It looks like the barrel adjuster is attached to the little chain coming out of the hub. This means the cable has a complimentary threaded piece of about 2 inches or so. Don't worry about turning the barrel adjuster. All these pieces should pivot freely. Do not use too much force. These things should move quite easily. It is possible the barrel adjuster is in fact attached to the cable and the little chain has the thread. I am not sure right now. But this doesn't change much.
Once you have the little chain coming out of the hub separated from the shifter cable, the black plastic pulley just comes off of the rear axle nut.
Once you get the black plastic pulley off, do notice one thing about the little chain. There should be an indicator of some sort. On sturmey archers it's a little blue spec of paint. This is for calibrating your hub later. When you're calibrating, this indicator has to be flush with an edge on the plastic pulley.
In any case at this point loosen the wheel and adjust it such that it is centered.
When you put the stuff back together, plop the shifter into 2nd. Then adjust the barrel adjuster until the indicator on the chain is aligned. I am making assumptions here that the T3 is anything like the Sturmeys.
If you do have a manual for your hub, take a gander at it, at least at the adjustment/calibration section. If not, take a look at this one: http://www.sturmey-archer.com/pdfs/S...ub_LTE_161.pdf. It's for a Sturmey hub that seems to have similar cable routing.
By the way is the distance between the chain and the frame constant? Or does it come in close then go away from the frame's tubing? If the former then your wheel just needs an alignment. If the latter then it may be the crank wheel. It may be bent.
BTW it's quite normal for the wheel to come out of alignment on bikes such as this, with horizontal drop outs. This happens if the lock nuts are too loose for the force you're putting out. I believe I had the same issue when I took delivery of one of my Dahons.
Also, since you need to loosen the cable and recalibrate the hub when you change flats (sometimes), might as well try it right off the bat.
Originally Posted by folder fanatic
Hi, yes i've got a local bike shop but their attitude is such that i'd rather struggle through the setup myself than go there on principle!
I'm not a complete dumbass and have bought all sorts of things off the internet for many years. Usually all is good but sometimes it's not. I bought the bike knowing that it would probably need a bit of tinkering but admit i'm suprised just how much tinkering it has needed.
Still, it's only a pushbike and i'm sure i'll get there in the end
I'll try your suggestions and see how i get on if i don't manage to fix it today by myself.
Thanks for the good luck!
Thanks for that. I got a couple of manuals with the bike but nothing specific about the hub so what you've put there is really helpful.
I figured out how to disconnect things at the back end by myself last night but didn't recalibrate afterwards so will follow your instructions and do that in a minute.
When i took it apart i did think about adding some washers to the outside of the assembly on the chain side so that the frame wasn't pulled so far towards the chain when everything was tightened. In the end i didn't bother as removing the wheel was proving to be tricky (i disconnected the brakes but when i realised the mudguard had to come off aswell i gave up!) and i doubt the washers would have changed much anyway.
The gap/lack of gap between the frame and chain is constant so the crankwheel is probably isn't bent.
I've been for a quick spin since reassembly and it still rides well despite me not calibrating the hub.
However, the chain/frame clearance still hasn't improved and i'm now having trouble keeping the chain tight enough after adjusting. It seems to loosen off after just a few meters riding but i think it was a bit too overly tight to begin with.
I'm loath to overtighten the wheel nuts so i'll just adjust the hub and see if the loosening continues or settles down. The wheel adjuster modification looks like a good idea.
To be honest, the chain was and still is only just 'kissing' the frame so i'll just have to add some padding to protect the frame. I guess i could have just done that in the first place but i wouldn't have had so much fun!
On the plus side, i'm learning quite a bit about bicycle mechanics!!!
All seems to be well now
One of the wheel reflectors was cracked so i went to Halfords to see if i could get a similar looking replacement. Even i could probably fit one of them without incident.
As i wheeled the Curve to the cycle spares, the young sales assistant came over for a chat and i told him of the problems i had. I hadn't even thought about getting Halfords to set the bike up so when he offered to take a look, i said i only really came in for a reflector but he's more than welcome to see if there was anything obviously wrong.
I was totally chuffed when he put it on their rig and said not to worry, he wouldn't charge me!
Anyway, he was pretty suprised that the chain touched the frame even after he'd aligned the wheel correctly. The only solution he could suggest was the same as mine- spacing the frame out with washers.
Unfortunately he couldn't find anything the right size so i popped home to get a handful of washers and left the bike there. I was delayed because i stopped to attend to a lad who had just crashed his bike by getting his umbrella and then his fishing rod through the spokes
When i finally got back to Halfords, the lad had adjusted the front brakes and was waiting for the washers to do the spacing on the hub. 5 minutes later, no more chain rub, aligned wheel, properly adjusted gears and correct chain tension. He did note that with the extra washers, the wheel nut would now not cover all the threads so to be careful tightening it in future.
The only thing not fixed was the reflector- apparently all the cool kids take them off and bin them
Big thanks to Halfords. I know they get a bad rap but i couldn't fault the lad and i got my bike setup for free, he kept to his word and refused to charge me.
I was starting to feel a little bit down about the bike so it's a big relief knowing that it's been tweaked by somebody in the trade.
That said, the chain tension has already slackened off again (although it seems to have stabilised now) so i'm wondering if that's just the newness of the chain or the axle that keeps slipping.
I admit to probably under-torquing the wheel nuts as they look so dainty but the lad in Halfords was a bit braver!
I think i'm just going to quit while i'm ahead for today and just enjoy riding it to work next week with a spanner handy just incase.
Thanks once again for the help.
Wow what an uplifting experience! I am glad that you are now set to enjoy your new bike in the matter that you should be. I am not familiar with the UK or it's geographical distances there, but perhaps you can now patronize this nice shop when you need to-and avoid that not-too-nice shop that you mentiioned. Many happy years of riding/ownership of your new Curve (I own the Piccolo and absolutely love it)!
Originally Posted by mattbike
Originally Posted by folder fanatic
I rode the Curve to work and back today without any hitches and loved every second of it. Bit achey now though hehe
I even managed to get away with taking the bike inside without folding it which is a whole lot easier than folding it!
Originally Posted by mattbike
I'm glad I found this thread. I have the exact same issue. I noticed it when I flipped the bike over to change my first flat. I was thinking washers, but wasn't sure if that was a good idea. Now that I know its ok, I just wanted to ask...did you use plain old hardware store type washers? Is there any way to figure out what size washer to use without trying a bunch (I don't have any lying around)? I don't have a caliper ruler, unfortunately. Maybe I should just buy one...What do you think?
Originally Posted by Caaah
I'm sorry you had the same issue as me with your Curve.
The washer/spacer i used was just one that Halfords (a local bike/auto dealer franchise) had lying around in a drawer. It's more or less identical to the washer/spacer already installed on the other side of the hub (sandwiched by the nut). It must be approximately 3mm thick (sorry about the metric system!) As it's so similar i would guess it was originally an axle-spacer from another bicycle. That said, i see no reason why you couldn't use a couple of standard washers instead which is exactly what i would have done. It's a shame that you're on the other side of the pond or i would have posted you a few.
I'm no mechanic so there might be another way to increase the clearance by fiddling with the hub but i didn't want to mess with that. It actually looks like Dahon forgot to fit a spacer seeing as there's the one on the other side?
I don't think that you would need to worry too much about measuring the exact thickness of the washer(s) that you use with a caliper. There seems to be a fair amount of tolerance in the frame so as long as the wheel ends up straight and the chain stops rubbing, you should be fine with a range of thicknesses.
The main thing that i would say is that once you fit a spacer bear in mind that the axle nut may not fully screw on the axle so be careful not to strip the thread when you tighten it as the nut has a special Sturmey Archer thread- as i found out when i stripped it
I also got fed up trying to maintain chain tension and wheel alignment so i modified a pair of these to fit:
All seems to be working well for now even though the tensioners have reduced the available threads for the axle nut still further.
Anyway, i hope that helps a bit and good luck!
Glad it's fixed. It sounds like the bike needs some kind of chain adjusters like my old motorbikes used to have. These consisted of a washer welded to a thin threaded bolt that was tightened onto a sort of folded channel on the end of the forks. You can see from these photos how it would work They hold the axel against the pull of the chain, an special problem with a motorised system that can pull damned hard.:
These ones are available on Amazon.com
Last edited by EvilV; 06-03-08 at 05:11 AM.
Ahhh, interesting. I didn't know about those chain adjusters.
I did actually go to the hardware store on Sunday to just get some regular washers. I took the washer from the other side with me for comparisons sake. Unfortunately, I couldn't find one that was a close enough match! I even bought what was closest, but it was just a teeny tiny bit too small. I guess I have to go with something bike specific. Maybe I'll go to a couple LBS and see if they have a spare one lying around.
Then, I'll look into the chain adjusters. Thanks for the help!