BIG chainrings
Printed From: BHPC Forum
Category: Public: Open to anyone
Forum Name: Wanted
Forum Description: You need something? Ask for it here
URL: https://forum.bhpc.org.uk/forum_posts.asp?TID=4925
Printed Date: 27 March 2026 at 4:57am
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Topic: BIG chainrings
Posted By: Yanto
Subject: BIG chainrings
Date Posted: 21 November 2013 at 2:50pm
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Hi, I'm after a chain ring, 130 bcd 5 arm, 75 or 80t. Cheers Ian |
Replies:
Posted By: BarneyH
Date Posted: 21 November 2013 at 7:19pm
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Ian Raptobike.com component shop and I think their standard as 130mm. Good luck Barney
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Posted By: Yanto
Date Posted: 21 November 2013 at 7:55pm
| Cheers Barney, i'll have a look. |
Posted By: Andrew S
Date Posted: 22 November 2013 at 12:13pm
| Try http://www.alligt.com/en/chain-rings" rel="nofollow - Alligt in the Netherlands - they do beautiful CNC chainrings up to 80T in 110 and 130mm BCD. They also do chainrings with built-in guards which are great for compliance with BHPC racing rules. |
Posted By: blogwat
Date Posted: 22 November 2013 at 3:17pm
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Hi Ian
I've got a seventy tooth if thats any good for you its 130 bcd shimano type
Jeff. ------------- when your up to your waist in aligators they forget to tell you you've got to clear the swamp |
Posted By: Yanto
Date Posted: 22 November 2013 at 4:53pm
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Andrew, Alligt had been mentioned to me, they seem to supply Europe with big rings. Them and Dutch Bike bits are the same price, Raptobite sell them with a small increase in price! Thanks for the offer Jeff, I'll do some calculations (or rather Sheldon Brown will) and PM you. |
Posted By: BarneyH
Date Posted: 22 November 2013 at 6:18pm
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Ian If trying to do gear calcs have you tried k gear from the kinetics site, I find it the most user friendly, its free and seems very reliable for all manner of odd set ups.. http://www.kinetics-online.co.uk/parts-accessories/gearing/k-gear-software/" rel="nofollow - http://www.kinetics-online.co.uk/parts-accessories/gearing/k-gear-software/
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Posted By: Yanto
Date Posted: 22 November 2013 at 7:42pm
| Easy to use Barney, but I don't understand gear inches or metres, or rather I can't translate them into speed. Mph/100rpm I can understand and "feel". |
Posted By: BarneyH
Date Posted: 24 November 2013 at 10:23am
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Ian I don't really understand what the numbers mean on the road either but what I do is to enter the current ratios I've got on whichever bikes I like and then enter the proposed set up to see how my current ratios compare to the proposed, its just a way of comparing to each other - I'm probably doing this all wrong but who cares, I just get out and ride whenever I can.
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Posted By: Andrew S
Date Posted: 25 November 2013 at 11:42am
Personally I find the European system of metres of development (distance travelled per pedal turn) a whole lot more understandable than 'gear inches', the imaginary diameter of some enormous penny-farthing wheel. |
Yanto wrote:Posted By: Yowie
Date Posted: 25 November 2013 at 5:32pm
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As Barney says, the way most people get to know and understand what gear inches are is by trial and experimentation. Looking at your favourite bikes and gears that you actually spend time in is a good method. Sheldon't Gain Ratio as he calls it is an additional factor relating to crank length, so if you're comparing a 170mm crank road bike with a 150mm crank recumbent, all other things being equal means that the gearing is 170/150 higher on the recumbent. Aerodynamics of course may affect your consideration of what the gear range should be, but don't go overboard. |
Posted By: Yanto
Date Posted: 25 November 2013 at 5:48pm
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I'm just replicating what is already on Wobbly Bob (80t). I'm hoping to stick a boom and BB in rather than the fragile Z cranks that are too easy to bend, I want to be able to mash it from the line, this will mean I can "grrrrrrr" like Barney then! On rooting around in the shed I might have stumbled across something which might mean not having to purchase a new ring after all. |
Posted By: Wyndrake
Date Posted: 25 November 2013 at 10:40pm
So Yanto, you've got nuclear mice in your shed too ....
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Posted By: Yanto
Date Posted: 25 November 2013 at 11:12pm
 shush, the technical inspector might be reading!
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