Shimano Alfine 8-speed hub

Betamax-

Betamax-

Betamax-

Associate
Joined
21 Mar 2010
Posts
143
Location
Islington, London
Hi all,

I just recently purchased my first bike!! I took it out for my first bike ride yesterday and managed to do 38 miles but struggled to keep up with a friend on a normal geared road/racer bike on the straights due to the hub gearing on my bike.

Does anyone know if I can change the gearing ratios on the hub set to give me a higher gearing ratio, so I can have some extra speed? The gears go up to 8 but I only ever seem to need to use from 5-8.

Im pretty sure this is my current ratios:

Gear Ratio 1 0.527
Gear Ratio 2 0.644
Gear Ratio 3 0.748
Gear Ratio 4 0.851
Gear Ratio 5 1
Gear Ratio 6 1.223
Gear Ratio 7 1.419
Gear Ratio 8 1.615
Gear Ratio 9
Gear Ratio 10
Gear Ratio 11
Axle Length 135mm
Over Locknut 187mm
Spoke Holes 32, 36H
Spoke Size 92.6mm
Sprocket Options 16, 18, 19, 20, 21, 22, 23T (16T: for Outward assembling only)

Im guessing I could put on a sprocket with more teeth but I have no idea where to get one that would fit.

Sorry im farily new to cycling so I dont know how/where to look!

The specs of my bike are here if you need to find the hub info:

http://www.on-one.co.uk/i/q/CBOOPOMPALF/on-one-pompetamine-alfine

Look forward to your response!!
 
Your current setup would give you these speeds @ 100rpm. Using 39/20.
1st 8.4
2nd 10.2
3rd 11.9
4th 13.5
5th 15.8
6th 19.4
7th 22.5
8th 25.6


Speed @ 100rpm with 39/18
1st 9.3
2ns 11.3
3rd 13.2
4th 15.0
5th 17.6
6th 21.5
7th 25.0
8th 28.4


You can change your front ring from a 39 to a 45 but that costs £80.

Would give you 45/20.

1st 9.6
2nd 11.8
3rd 13.7
4th 15.6
5th 18.3
6th 22.4
7th 25.9
8th 29.5
 
ok thanks man. I did a bit of research myself and thought maybe if I changed the rear sprocket to 18t instead of the current 20t it might help. do you think that would work? rear sprocket is only £9 so makes it a bit cheaper...

oops I should have read the second bit of the ratios!! thanks for your help!!!!
 
Last edited:
I have a Pompetamine Versa Pro (the drop bar version of your bike), which came with a 48t chainring and an 18t sprocket. This was much too high for me, and so I replaced it with a 44t chainring and a 22t sprocket. I found changing the sprocket to be a real pain due to the difficulty of getting the snap ring back on; I had to ask for help in the end as I just couldn't get it to go on. The Nexus sprockets that Jonny //M linked to will work fine on your Alfine hub, in case you're not sure. Keep in mind that you'll have to shorten your chain if you do fit a smaller sprocket, as you won't be able to take up enough of the slack by moving the hub in the fork end.
 
Saundie said:
I have a Pompetamine Versa Pro (the drop bar version of your bike), which came with a 48t chainring and an 18t sprocket. This was much too high for me, and so I replaced it with a 44t chainring and a 22t sprocket. I found changing the sprocket to be a real pain due to the difficulty of getting the snap ring back on; I had to ask for help in the end as I just couldn't get it to go on. The Nexus sprockets that Jonny //M linked to will work fine on your Alfine hub, in case you're not sure. Keep in mind that you'll have to shorten your chain if you do fit a smaller sprocket, as you won't be able to take up enough of the slack by moving the hub in the fork end.
Click to expand...

Nice! I was looking into the drop bar version but decided against it as I have only just started cycling again.. before last weekend I hadnt been on a bike in about 7 years!

I think im probably going to get the 18t sprocket, ive found an alfine one on wiggle that will fit and its a bit cheaper. Ill see if that makes any difference.

When you changed the chainring, could you put any make on there or was it a specific shimano one?

Thanks for the tip on the chain, was hoping to just use the horizontal drop outs to tension the chain.

Have you got any pics of your bike?? Id like to see how you got it set up!

:D
 
Betamax- said:
I think im probably going to get the 18t sprocket, ive found an alfine one on wiggle that will fit and its a bit cheaper. Ill see if that makes any difference.

When you changed the chainring, could you put any make on there or was it a specific shimano one?

Thanks for the tip on the chain, was hoping to just use the horizontal drop outs to tension the chain.

Have you got any pics of your bike?? Id like to see how you got it set up!

:D
Click to expand...
My bike has a different crankset to yours, so the chainring I replaced it with won't work for you. You would need to go for a 110 PCD chainring instead, however the make doesn't matter. Thinking about the chain length again, you might not need to shorten it given the relatively small decrease in sprocket circumference. It depends on how much slack there is with the current set up, though I suppose you'd only have to remove one link from the chain in either case. You'll need to make sure that you get the chain tension right when you re-install the back wheel, otherwise the chain could slip or fall off.

I don't have any photographs of my bike unfortunately, and they have removed it from the On-One site now :(
 
Ok thanks.

Do you know if I can remove the plastic guard that covers the chainring? Would like it so I can see the chain around the chainring.. purely for looks :)
 
I don't see why not, though I would leave it on personally, as it'll help you avoid getting oil on your leg/clothes.

One other thing that I'm not sure about is whether or not all 110 PCD chain rings are the same width. The track chain ring that I have is available in either 1/8 or 3/32, so I had to make sure it matched the rest of my setup. Hopefully somebody else can answer this!
 
You must log in or register to reply here.
Back
Top Bottom