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brommie 11-10-07 07:33 AM

Brompton Wide-ratio gears
 
Dear Bromptonauts and other riders of folders...

Today I fitted a Highpath (18/12 tooth sprockets) on my Brompton T6.
Chain wheel is 50 t.

maybe someone else did the same. Just curious.


A trip on my Brommie makes me smile...

yangmusa 11-10-07 10:46 AM

Seems like a worthwhile increase in gear range. How much is the kit from Highpath?

Sammyboy 11-10-07 03:31 PM

I'm just looking at their site. I've never seen them before. I'm not seeing any reference to SA hubs though (I'm seeing LOTS of other interesting things though!)

brommie 11-11-07 04:17 AM

the costs
 
Quote:

Originally Posted by Sammyboy (Post 5610417)
I'm just looking at their site. I've never seen them before. I'm not seeing any reference to SA hubs though (I'm seeing LOTS of other interesting things though!)

Hi Sammyboy,

Correct, you will not find them on their site.
The price is 46,50 English Pounds, wich include post to the Netherlands.


greatings.

invisiblehand 11-11-07 03:38 PM

Quote:

Originally Posted by brommie (Post 5608642)
Dear Bromptonauts and other riders of folders...

Today I fitted a Highpath (18/12 tooth sprockets) on my Brompton T6.
Chain wheel is 50 t.

maybe someone else did the same. Just curious.


A trip on my Brommie makes me smile...

Excellent ...

I remember the following thread on Brompton Talk

The combined 12/18 sprocket was supplied by Highpath Engineering (their website at http://www.highpath.net/cycles/index.html is very educational, but doesn't actually mention this 12/18 sprocket) and cost 39 pounds sterling.

I spent almost 2 days installing this sprocket set, filing the end of the
chainstay, testing and taking the rear wheel off and back on quite a few times, but eventually gave up getting a clean gear change. The chain would 'ride' on the top of the teeth 18T sprocket, and immediately jam between this and the end of the seat stay. This happened both when testing in my workshop, and when out riding.

However Chris Bell at Highpath Engineering has been very helpful on the phone,
and has offered to grind down the teeth on the 18T sprocket a bit, and I'll have one last try when he has done this. I have noticed that the standard 15T Brompton sprocket has some teeth which are shorter than the others, and I wonder if this is what Chris has in mind?

I'll let you know how I get on, but in the meantime, I'd be very interested to
hear from any others in this newsgroup who have successively installed this sprocket set!

I don't know whether Highpath produce 12/17 or 13/18 versions of the sprocket
set (or whether I'd have the patience to try them if I can't get the 12/18 to work!)


Did you run into issues installing the 12/18? Were there any non-standard procedures such as filing down a chainstay or sprocket teeth?

brommie 11-12-07 02:52 PM

Quote:

Originally Posted by invisiblehand (Post 5614994)
Excellent ..

Did you run into issues installing the 12/18? Were there any non-standard procedures such as filing down a chainstay or sprocket teeth?

Nothing special, but you have to remove a few milimetres from one of the rearframe tubes ( so there is enough place for the 18 t sprocket).
Before the wide gear sprocket I already had a 13 tooth and a 17 tooth sprocket, so I didn't need to fit in a new link in the chainring.

I just followed the article about placing the wide gear sprockets as placed in A to B Issue 47. Get on the bike and go!

brommie 12-22-07 09:20 AM

no one else
 
I'm still wondering if someone else changed the sprockets on his folder (perhaps even a Brompton)?
And how the bike may have changed.

Jos

Simon elsdon 08-28-08 02:20 PM

brompton 12 18
 
did you ever sort out this sprocket? Simon

brommie 09-01-08 11:19 AM

Simon,
What do you mean by sort out?(English is not my native language) but I've until now never had any problems with this sprocket. I'm just back from Italy, did take my Brompton with me, and did some hills near lake Garda and even then no problems.

Simon elsdon 09-09-08 03:59 PM

brompton gearing
 
Highpath have stopped making their 18/12 sprocket which may be related to the difficulties some have had -you mention a 17/12 sprocket -where did you get this from?
regards
simon

Simon elsdon 09-09-08 04:02 PM

brompton gearing
 
sort out = fix = did it work -in fact Highpath have stopped making this sprocket so I assume others had a problem regards simon

brommie 09-11-08 12:12 PM

13 / 17
 
Before the wide gear sprocket I already had a 13 tooth and a 17 tooth sprocket, so I didn't need to fit in a new link in the chainring.

I just bought a 17 sprocket in a bike shop, showing them the 15 sprocket (original). Seems nothing special at all for them. They had plenty of these 17 sprockets.

brommie 09-11-08 12:14 PM

pictures
 
You can see a picture on y Flickr page

brommie 09-12-08 09:40 AM

no more Highpath wide ratio sprockets?
 
Just received an email from Chris Bell. He has no more sprockets left and maybe he will make more if demands picks up significantly.!
So I sign in for two sprockets, hope there will be more demands, because the sprockets work great.


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