Go on Hope gis a jo...
 

  You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more

[Closed] Go on Hope gis a job- 28 tooth chain ring

24 Posts
20 Users
0 Reactions
181 Views
Posts: 1384
Free Member
Topic starter
 

Reading the review of the narrow wide rings "£40 odd?, i could make one for that"

So some measureing and CADing and off cuts of ali here we are. A 28 tooth ring on a 104 pcd fitting. Kind of in between where the middle and inner rings would be.

[url= http://farm3.staticflickr.com/2844/10826502556_3e161514cf_c.jp g" target="_blank">http://farm3.staticflickr.com/2844/10826502556_3e161514cf_c.jp g"/> [/img][/url]
[url= http://www.flickr.com/photos/86019718@N05/10826502556/ ]chain ring assembled[/url] by [url= http://www.flickr.com/people/86019718@N05/ ]Dean-B1[/url], on Flickr

[url= http://farm4.staticflickr.com/3702/10826477595_f55b8646fb_c.jp g" target="_blank">http://farm4.staticflickr.com/3702/10826477595_f55b8646fb_c.jp g"/> [/img][/url]
[url= http://www.flickr.com/photos/86019718@N05/10826477595/ ]chain ring assembled[/url] by [url= http://www.flickr.com/people/86019718@N05/ ]Dean-B1[/url], on Flickr

[url= http://farm8.staticflickr.com/7331/10826637944_14fd98bbc5_c.jp g" target="_blank">http://farm8.staticflickr.com/7331/10826637944_14fd98bbc5_c.jp g"/> [/img][/url]
[url= http://www.flickr.com/photos/86019718@N05/10826637944/ ]chain ring assembled[/url] by [url= http://www.flickr.com/people/86019718@N05/ ]Dean-B1[/url], on Flickr

bit of fine tuning and it should be good to go on the bike.

 
Posted : 12/11/2013 10:07 pm
Posts: 646
Full Member
 

ooh, that's nice. If you dont like it send it my way.

 
Posted : 12/11/2013 10:09 pm
Posts: 33980
Full Member
 

doffs cap

 
Posted : 12/11/2013 10:11 pm
Posts: 43345
Full Member
 

Who's a clever boy then?

 
Posted : 12/11/2013 10:11 pm
Posts: 0
Free Member
 

If you need an 80bcd 28 tooth testing I'm your man 😆

 
Posted : 12/11/2013 10:29 pm
Posts: 5111
Full Member
 

Haven't you got a kid to breast feed Gee? 😉

 
Posted : 12/11/2013 10:32 pm
Posts: 0
Free Member
 

Just doing it!, he's just dozed off too!. A man can dream can't he!. Need a thick thin ring for the raceface double. Sram do an 80 bcd double too so surely its gotta be worth someone doing one 😀

 
Posted : 12/11/2013 10:48 pm
Posts: 4267
Full Member
 

Nice idea using a carrier/bash to mount to the 104 BCD. What's the actual BCD of the 28 ring (I'm assuming they're 2 separate parts- the carrier and the ring?)

Any way to reduce the offset - it's going to make your chain line a bit off - but hopefully ok in small-small.

 
Posted : 12/11/2013 11:58 pm
Posts: 97
Full Member
 

Good work that man.
I used to program stuff like that for [i]fun[/i] when I was a setter.

 
Posted : 13/11/2013 12:14 am
Posts: 219
Free Member
 

Nice work fella.
Don't want to wee wee on your firework but what about hardening?

 
Posted : 13/11/2013 12:25 am
Posts: 0
Free Member
 

Looks good to me - well done mate!

 
Posted : 13/11/2013 7:55 am
Posts: 0
Free Member
 

good work!!

 
Posted : 13/11/2013 11:10 am
Posts: 17
Free Member
 

whats the cost price 😉

 
Posted : 13/11/2013 11:13 am
Posts: 0
Free Member
 

Can you do me a 32t please? #seriousquestion

 
Posted : 13/11/2013 11:23 am
Posts: 0
Free Member
 

Can you do me a [s]32t[/s]34t please? #seriousquestion
+1

 
Posted : 13/11/2013 11:25 am
Posts: 0
Free Member
 

28 tooth?! (Well someone had to say it 🙂 ) Nice work though.

 
Posted : 13/11/2013 11:38 am
Posts: 1
Free Member
 

Can you make Mint Sauce Key rings?

 
Posted : 13/11/2013 11:40 am
Posts: 41642
Free Member
 

Can you do me a 34t please?

Missing the point? Every man and his dog does 104mm 32t/34t chainrings. It's the 28t on 104mm that's individual.

 
Posted : 13/11/2013 12:34 pm
Posts: 1384
Free Member
Topic starter
 

Thanks for the comments.

An evening in the garage paying with the dirty words in the bike industry (standards and tolerances).

So not all chain ring bolts have the same thread (or diameter) and arm thickness between the outer and middle ring can vary up to 1mm?

Anyway some work with the file to get the carrier to clear the crank and it's on.

Am going to make another chain ring as the inner plates of the chain have a square notch on the outer edges which is catching plus i think some clearance on the tooth profile might be needed.

[url= http://farm6.staticflickr.com/5476/10843550915_03dfc9007c_c.jp g" target="_blank">http://farm6.staticflickr.com/5476/10843550915_03dfc9007c_c.jp g"/> [/img][/url]
[url= http://www.flickr.com/photos/86019718@N05/10843550915/ ]fitting 28 tooth[/url] by [url= http://www.flickr.com/people/86019718@N05/ ]Dean-B1[/url], on Flickr

Also thinking you only have to chamfer on side of the teeth as it's only the top third of the cassette that creates a high chain angle.

 
Posted : 13/11/2013 9:33 pm
Posts: 1384
Free Member
Topic starter
 

Well its survived a peak ride, all the fun of the pootle, chain only came of when we were stood still and i back pedaled. Not bad considering no cain guide or clutch mech. Also managed round on a 11-34 cassette. On the mk2 chain ring that now has some clearence machined into it for the chain.

 
Posted : 01/12/2013 5:38 pm
 hora
Posts: 0
Free Member
 

Fantastic! 😀

 
Posted : 01/12/2013 5:51 pm
Posts: 10340
Full Member
 

Very nice!
I'd be interested to know if you ever find that you're under-geared.
Occasionally people with a 30t complain about it, but I'm not convinced it would be a big deal to me.

 
Posted : 01/12/2013 5:51 pm
Posts: 0
Free Member
 

Good work 🙂

 
Posted : 01/12/2013 5:53 pm
Posts: 87
Free Member
 

Nice bit of CNC work. And quite a neat solution to a 28 tooth on a 104 BCD. Do you think you could make off set machined spacers to fit the crank arms with an M6 bolt hole for the 28 tooth ring on a smaller BCD ?

 
Posted : 01/12/2013 6:49 pm
Posts: 1384
Free Member
Topic starter
 

Very nice!
I'd be interested to know if you ever find that you're under-geared.
Occasionally people with a 30t complain about it, but I'm not convinced it would be a big deal to me.

Well for normal pottering say 10-15mph its fine, climbing was ok for what we covered.
As for spinning out in the impromptu race for cake at the end of the day 20mph was just managable and i "spun out" at 23mph.

ive a graph somewhere comparing ratios (all other things being equal)

 
Posted : 01/12/2013 6:52 pm

6 DAYS LEFT
We are currently at 95% of our target!