Chain is too loose on hub gear bike

Cianos

Hey there,
My friend has a hub gear bike, and the chain is resting too loose to the point where it keeps falling off. I've tried searching google for a solution but haven't had any luck. I've no idea how this would be fixed other than shortening the chain, but I don't think that's the best solution as I'm pretty sure it's the chain that came with the bike which would mean it was working before with that length of chain.

Any help appreciated!

Chains tend to get a bit longer as they wear. If you leave it too late to replace the chain the increased length between links can wear the sproket and chainring teeth. I'd advise to check the chain for wear. If it's 1/2'' pitch chain, measure 10 links, should come to 5''(I think), much longer and the chain is dying. Has the bike got horizontal dropouts? As a temporary fix you could slide the wheel back to take up the slack in the chain.

DualFrontDiscs

I know that I pulled the hub forwards on the drive side just through sheer force, or loose nuts.

Is the wheel centred in the frame? When it went wrong for me, the chain was loose and the wheel was off centre.

Regards,

DFD

Morgan

Loosen axle nuts.

Pull wheel back to tighten chain (not too much)

Tighten axle nuts.

copacetic

most hub geared bikes don't have horizontal dropouts, it more likely has an eccentric bottom bracket. OP what kind of bike is it?

Morgan

copacetic wrote: »

most hub geared bikes don't have horizontal dropouts

Yes they do. Mostly.

copacetic

Morgan wrote: »

Yes they do. Mostly.

Care to point one out, you'd be helping me out? I've been looking for a while and none of the current models from any major brand do as far as I can tell.

Morgan

Here's a few:

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_240363_langId_-1_categoryId_165534

http://www.chainreactioncycles.com/Models.aspx?ModelID=36360

http://www.genesisbikes.co.uk/bike/io_id

http://www.chainreactioncycles.com/Models.aspx?ModelID=39974

http://www.dawescycles.com/p-143-diploma-gents.aspx

copacetic

jeez morgan, you are clutching at straws there!

I've been looking hard for a decent city bike with alfine and can't find one with horizontal dropouts anywhere (as you must have discovered during your search), unless you get one built yourself like a roadrat or similar.

Civilian_Target

I have a hub gear bike.

When this happens to me, I replace the chain. Evidently it has stretched and is now too long. They're not expensive, and for the 6 months of wear you might save by removing some links, what's the point?

Morgan

copacetic wrote: »

jeez morgan, you are clutching at straws there!

I've been looking hard for a decent city bike with alfine and can't find one with horizontal dropouts anywhere (as you must have discovered during your search), unless you get one built yourself like a roadrat or similar.

Most city bikes with 7+ gears spec the Nexus rear hub - I'm not sure what the diff is between this and the Alfine.

http://www.giant-bicycles.com/en-GB/bikes/lifestyle/2466/32858/

http://www.trekbikes.com/uk/en/bikes/urban/soho/soho/

http://www.specialized.com/us/en/bc/SBCBkModel.jsp?sid=09SanFrancisco&eid=178

(sliding dropouts on the last two)

kona

The whole point of horizontal dropouts is so that you can tension the chain. BMX have horizontal, proper singlespeed and fixie frames have horizontal.

Vertical dropouts and single speed/fixed/internal hub is a waste of time, you cant tension the chain correctley, any manufacturer speccing vertical dropouts with this combination, are just being cheap.

If you want fixed/singlespeed or internal hubs, make damn sure it has horizontal dropouts.IMO.


RE: Chain length,

The chain stretches in each link, so its not a matter of shortening it, you need to replace it as has been said.

You an buy BMX chain tensioners to help get it spot on.

There isnt much difference between alfine and nexus, it depends on your use. Its like deore and deore XT.

penexpers

Morgan wrote: »

Most city bikes with 7+ gears spec the Nexus rear hub - I'm not sure what the diff is between this and the Alfine.

Alfine would be considered higher quality than Nexus.

penexpers

kona wrote: »

The whole point of horizontal dropouts is so that you can tension the chain. BMX have horizontal, proper singlespeed and fixie frames have horizontal.

Vertical dropouts and single speed/fixed/internal hub is a waste of time, you cant tension the chain correctley, any manufacturer speccing vertical dropouts with this combination, are just being cheap.

Well you can do fixed with vertical dropouts, but you can use a chain tensioner to tension the chain for single speed or internal hub. This is what I used myself and it's quite effective.

copacetic

Morgan wrote: »

Most city bikes with 7+ gears spec the Nexus rear hub - I'm not sure what the diff is between this and the Alfine.

http://www.giant-bicycles.com/en-GB/bikes/lifestyle/2466/32858/

http://www.trekbikes.com/uk/en/bikes/urban/soho/soho/

http://www.specialized.com/us/en/bc/SBCBkModel.jsp?sid=09SanFrancisco&eid=178

(sliding dropouts on the last two)

cmon man, they don't, any decent bike comes with alfine, not nexus, it's a massive step up from the nexus hub. Shimano spec that it shouldn't go in a horizontal dropout design, it should be speced with an eccentric bottom braket or the alfine chain tensioner device.

and as you've found the last 2 don't have horizontal dropouts they have a weird mildly adjustable frame design that messes up the brakes if you try to do anything. The Giant again doesn't have proper horixontal dropouts, just tiny adjustment in a old fashioned frame design.

I give up, you'll just tell me that black is white next.

copacetic

kona wrote: »

The whole point of horizontal dropouts is so that you can tension the chain. BMX have horizontal, proper singlespeed and fixie frames have horizontal.

Vertical dropouts and single speed/fixed/internal hub is a waste of time, you cant tension the chain correctley, any manufacturer speccing vertical dropouts with this combination, are just being cheap.

If you want fixed/singlespeed or internal hubs, make damn sure it has horizontal dropouts.IMO.


RE: Chain length,

The chain stretches in each link, so its not a matter of shortening it, you need to replace it as has been said.

You an buy BMX chain tensioners to help get it spot on.

There isnt much difference between alfine and nexus, it depends on your use. Its like deore and deore XT.

not true, eccentic bottom brackets are more expensive if anything and the likes of cannodale, charge all spec same.

personally I don't like them as they appear to be unreliable.

t0mm

copacetic wrote:

not true, eccentic bottom brackets are more expensive if anything and the likes of cannodale, charge all spec same.

It doesn't matter to the manufacturers if they spec the bike with more expensive parts, they pass the cost onto you. It is more expesive for them to construct two different frames, by using the same frame and differing the spec they can just have a pile of frames and spec them according to demand, with two different types of frame they run the risk of ending up with a pile of bikes they can't sell, and can't change spec to ones they can sell.

kona

copacetic wrote: »

not true, eccentic bottom brackets are more expensive if anything and the likes of cannodale, charge all spec same.

personally I don't like them as they appear to be unreliable.

How is that not true? What I was saying is that any SS without a way of tensioning the chain is a waste of time. I never mentioned eccentric bottom brackets or hubs because, they are not as common or indeed as you say reliable(IMO) as a simple chain tensioner on a horizontal dropout. Vertical dropouts are fine with eccentric bottom brackets or indeed than arm tensioner thingy if they gave the correct parts fitted. However they are just a bigger pain in the hole.
Horizontal is still IMO easier and better.
Problem arises with many vertical dropout SS with no way of tensioning the chain properly.

Any bike manufacturer who specs singlespeed with vertical dropouts is cheaping out because they are obviously not tieing themselves down with two different frames as mentioned.

kona

penexpers wrote: »

Well you can do fixed with vertical dropouts, but you can use a chain tensioner to tension the chain for single speed or internal hub. This is what I used myself and it's quite effective.

I never said that you couldnt. Buy IMO the only reason most people are using fixed gear and vertical dropouts is because there is a load of these frames, and they are quite cheap to buy.
IMO the chain tensioners for vertical dropouts(i presume like nexus and alfine with the arm that attaches to the chain stay) are a solution to a problem created by using vertical dropout.
The chain tensioners for horizontal dropouts are cheaper, and IMO easier to use.

I still stand by my opinion that any manufacturer(different to custom builds) that speccs verticaldropouts on a SS is producing a lower quality bike.

RE: Nexus+Alfine, shimano dont specifiy horizontal or vertical hubs, to make their product more sellable to more mass produced(and cheaper) bikes, they have as you said the L/H arm tensioner, but they also spec a unique washer to a frame depending on the angle of the dropout to the axle....

penexpers

kona wrote: »

I never said that you couldnt. Buy IMO the only reason most people are using fixed gear and vertical dropouts is because there is a load of these frames, and they are quite cheap to buy.
IMO the chain tensioners for vertical dropouts(i presume like nexus and alfine with the arm that attaches to the chain stay) are a solution to a problem created by using vertical dropout.

The Alfine chain tensioner (and indeed most chain tensioners) are just like a normal derailleur and even attach to the derailleur hanger found on most vertical dropouts.

I still don't think it's possible to get fixed using vertical dropouts.

http://sheldonbrown.com/fixeda.html#vertical

kona

penexpers wrote: »

The Alfine chain tensioner (and indeed most chain tensioners) are just like a normal derailleur and even attach to the derailleur hanger found on most vertical dropouts.

I still don't think it's possible to get fixed using vertical dropouts.

http://sheldonbrown.com/fixeda.html#vertical

Ive come across plenty of SS/fied using vertical dropouts, trying to get any tension on the chain is a pain in the hole.

Thank-you cheapskate hipsters:P

sheldon brown wrote:

Even the chain tensioners used for downhill mountain bike racing are not strong enough to withstand the stress of resisting the pedals. These tensioners have to clamp on to the chain stay, which is more or less round. There is no way to make one that would be secure, short of installing some sort of brazed-on fitting

Thats the tensioning arm that goes onto the chainstay ala, nexus and alfine, that i mentioned.Its also used with roller brakes.
Apart from a friction fit he doesnt really mention any other ways. Im intregued about the tensioner you have, seems a good idea.

Morgan

copacetic wrote: »

I give up, you'll just tell me that black is white next.

I was just pointing out that the vast majority of bikes which have a hub gear also have horizontal dropouts. Eccentric BBs are to be found in certain higher end models.

(If you're looking for a suitable bike - the ones with the sliding dropouts above would work fine - the brake mount moves with the dropout. Also, Alfine will work fine with horizontal dropouts, track ends or vertical dropouts depending on the fittings used.).

penexpers

kona wrote: »

Thats the tensioning arm that goes onto the chainstay ala, nexus and alfine, that i mentioned.Its also used with roller brakes.
Apart from a friction fit he doesnt really mention any other ways. Im intregued about the tensioner you have, seems a good idea.

He is specifically talking about fixed gears there, not singlespeed/hub gears. The chainstay ones are fine for singlespeed/hub gears.

Right now I have this tensioner



I also have this one in my parts bin



Both of them attach to the derailleur hanger using the standard derailleur bolt.

kona

copacetic wrote: »

jeez morgan, you are clutching at straws there!

I've been looking hard for a decent city bike with alfine and can't find one with horizontal dropouts anywhere (as you must have discovered during your search), unless you get one built yourself like a roadrat or similar.

why not just buy a abike with horizontal dropouts, get a wheel build up with a alfine hub, and sell the nexus one?

You probably have the subway8 with alfine for around the 650 mark.

kona

penexpers wrote: »

He is specifically talking about fixed gears there, not singlespeed/hub gears. The chainstay ones are fine for singlespeed/hub gears.

Right now I have this tensioner



I also have this one in my parts bin



Both of them attach to the derailleur hanger using the standard derailleur bolt.

That alfine one looks sexy. The only problem is that its loosing the "simplicity" and adding another part that is the main point people put forward with SS and fixed.

If you have track ends or horizontal dropouts then you keep the simplicity.

copacetic

kona wrote: »

why not just buy a abike with horizontal dropouts, get a wheel build up with a alfine hub, and sell the nexus one?

You probably have the subway8 with alfine for around the 650 mark.

so far it seems buying these hubs as parts is nearly the same as buying one with a bike attached! but I am looking at maybe settling for something like a charge tap with the nexus and horizontal dropouts rather than the mixer with alfine and eccentric bottom brackets. Save a few hundred too I suppose.

I'm still a little undecided, I like the looks and practicality but have heard a lot of bad reports of long term trouble both with the nexus hubs and the eccentric brackets. Alfine is supposed to resolve a lot of the hub issues but it is mostly on higher end bikes with the eccentric brackets. Not much point paying the premium and having more trouble than a std geared setup!

kona

copacetic wrote: »

so far it seems buying these hubs as parts is nearly the same as buying one with a bike attached! but I am looking at maybe settling for something like a charge tap with the nexus and horizontal dropouts rather than the mixer with alfine and eccentric bottom brackets. Save a few hundred too I suppose.

I'm still a little undecided, I like the looks and practicality but have heard a lot of bad reports of long term trouble both with the nexus hubs and the eccentric brackets. Alfine is supposed to resolve a lot of the hub issues but it is mostly on higher end bikes with the eccentric brackets. Not much point paying the premium and having more trouble than a std geared setup!

Nexus is fine when set up, the only problem is that, they have to be sent off to shimano if they have to be repaired. This is the main drawback, and in fairness its quite a big one.
Have you looked at similar such as rolhoff hubs, they are ment to be excellent.

I didnt realise alfine was so expensive! Id personally go with nexus, I cant justify such a crazy price difference.

DualFrontDiscs

kona wrote: »

Nexus is fine when set up, the only problem is that, they have to be sent off to shimano if they have to be repaired. This is the main drawback, and in fairness its quite a big one.
Have you looked at similar such as rolhoff hubs, they are ment to be excellent.

Any thoughts on repairing a Rolhoff without returning it?
DFD.

kona

DualFrontDiscs wrote: »

Any thoughts on repairing a Rolhoff without returning it?
DFD.

wouldnt even attempt to open it TBH,:o just send it back and get sombody who is experienced with them to fix it. It would be faster and cheaper in the long run.

Civilian_Target

Does it matter? Certainly, I have a SRAM-7 that's fast approaching 40,000km with absolutely no problems. I've had to replace the clapper box twice, they only seem to live about 15,000km, but the gear itself just keeps on going.

blorg

kona wrote: »

I didnt realise alfine was so expensive! Id personally go with nexus, I cant justify such a crazy price difference.

If you think Alfine is expensive you would love the price of Rohlhoff.

You can't run fixed with a tensioner. Here's a very tasty Alfine bike using track ends (presumably with road spacing.)