ISO 20-22 tooth chainring

[Bernard Duhon]

Going low

Looking for a 20 tooth ( will take a 22 tooth ring) 74 bcd 5 bolt chainring

9-10 speed compatible (non-HG)

For Sugino crank

 

I have scoured the internet & found nothing.

 

I see “vintage” 20 tooth on ebay.  That probably means less than 8 speed & not compatible with 9-10 speed chains.   

 

If you don’t have one can you point me to a seller with one.

 

 

Yours sincerely,

 

Bernard F. Duhon

111 Concord Street, Suite B
P.O. Box 1169
Abbeville, LA 70511-1169
Telephone - (337) 893-5066
Fax - (337) 893-0030
E-mail - ber...@bernardduhon.com

 

[Alex Wetmore]

Unfortunately you can't make a 20 or 22t 74mm BCD chainring, the bolts would interfere with the chain.  The old ones that you are finding were adapters (Avid Microdapter is one that I remember) that only worked on cranks without integrated spacers so that the adapter could use the physical space of the spacers.

Now that very wide range cassettes are commonplace I would suggest looking for a wider range cassette instead of a smaller chainring.

Alex

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From: 65...@googlegroups.com <65...@googlegroups.com> on behalf of Bernard Duhon <ber...@bernardduhon.com>
Sent: Monday, October 17, 2022 11:54 AM
To: 65...@googlegroups.com <65...@googlegroups.com>
Subject: [650B] ISO 20-22 tooth chainring

 

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[daxo potato]

you cannot find it because it does not exist. 24T is as small as can fit on 74BCD

https://sheldonbrown.com/cribsheet-bcd.html

if you are really looking to go lower gear, I'd recommend a cassette with larger cogs rather than a smaller chainring, I'm told less torque on the hub and less wear on the chainring and chains

cheers and good luck

Dave how low can you go? in NY

[Michael Wong]

At least one adapter, the Limbo Spider, used Suntour freewheel cogs. 

I believe it could go as low as 16T. But as above, I think you need a crank without inner bosses.

I have one I might part with!

To view this discussion on the web visit https://groups.google.com/d/msgid/650b/CAKihenrXKOK66ou2Q1%3D8X7%3DJfzzaS3y3ogPijU1y3K4HRhmXzg%40mail.gmail.com.

[Mitch Harris]

I had a 20t running on an Avid Mircrodaptor, and it worked well. I had it mounted on A SunTour XC pro crank, and the other SunTour mtb cranks, IIRC. I think it worked on Shimano XT/DX cranks too. But as others said, it works on cranks that require the spacers for the smallest ring. 

Another option for a 20t small ring is to use a 94/58 BCD five bolt triple crank. Shimano's version was 94/58 and SunTour's original Micro-Drive cranks were 94/56, I think. So the small ring is not compatible. I think the Avid Microdaptor used the Shimano 58mm BCD rings. Most of these 5 bold 94/58 BCD cranks came with 22t small rings (22/32/42) so you had to source a 20t. These 94/58 BCD five bolt cranks were only a standard in the late/mid-90s and the four bold 94 BCD crank appears sometime in the late 90s. But there are still companies that make five bolt 94/58 rings. At least you can still find them. IRD is out of stock but appears to still make their Defiant 94 BCD double but never did that one with as a triple with 58 BCD. I seem to recall they once offered a 94/58 triple though. 

SunTour Micro-Drive of course for a 20t too, but those will be a lot more rare than the five bolt 94/58 that were standard for 3 years or so with Shimano mtbs. 

Any of these solutions is interesting but more difficult to find, if you're starting from scratch, than a wider range cassette with a rear derailleur that can manage it. 

--Mitch 

[Bernard Duhon]

Thanks for response

I have a campy wheel & too expensive to change out the phil wood hub body  to shimano.

So larger cassete is not an option ( 11 speed is 32t max)

Bernard F. Duhon

111 Concord Street, Suite B
P.O. Box 1169
Abbeville, LA 70511-1169
Telephone - (337) 893-5066
Fax - (337) 893-0030
E-mail - ber...@bernardduhon.com

 

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[daxo potato]

might be more than you want to get into, but you might be able to disassemble a cassette with the gearing you desire (sunrace and micro shift both make reasonably priced 11 speed, loose cog cassettes) and reassemble it with campy spacers. some experimenting will be necessary, but might be interesting if you are willing to tinker. i read a forum thread about doing exactly this, only with 10 speed, but i believe it can be done.

*I INVITE CORRECTIONS IF I AM MISTAKEN!* i don't have anything campy (and this issue is yet another reason for that!) nor do i have anything over 9 speed (and prefer fixed gear!) so i could be just completely wrong. 

cheers and good luck!

dave "why so many gears?" in NY

[satanas]

The best solution - if it will fit your cranks - will be an Avid MicroAdapter with a 20-22T ring. These turn up on eBay occasionally, and the rings aren't hard to find. Otherwise it's new freehub body or new crankset time. The other adapters that will take <24T rings fit in the same way, but the Avid is the nicest and best made that I've seen.

Also, the smallest rings for 74 BCD cranks were 23T, made by PMP to fit their XP-RR 2x MTB cranks, but the bosses on the cranks were slightly relieved on the outside for chain clearance; I have a set.

A complete used wheel with a Shimano freehub body might be cheaper than a Phil freehub body, but even so 24x36 is a higher gear than 20x32...

Later,

Stephen

[Squire Black]

If you want to see an Avid Microadaptor, there was one on eBay (now sold): https://tinyurl.com/2bp9j542

The 'bay also has nice-looking pair of Deore LX 94–58 BCD 5-bolt cranks for a reasonable price (and 20% off with code SHIPTODAY): https://www.ebay.com/itm/255561847055

Disclaimer: Not my listings, no skin in his game, and have just pulled off my triple crankset and replaced it with a wide-ratio double and a larger cassette. 

[Michael Wong]

Here's another view of the Limbo Spider, which can go all the way to 16t:

https://www.retrobike.co.uk/threads/white-industries-groupo.327471/page-3

Another pricey option is a White industries VBC crankset, which lets you run any inner 5 arm chainrings. 

My brother found someone who makes custom rings who'll do a 19T for $25

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[Stephen Poole]

Bear in mind there is a limit (on a bicycle) to how slowly one can go before "stalling" becomes a problem; tricycles can go more slowly as they don't need to balance. This is less of an issue on smoothish bitumen, but offroad even small rocks or holes will stop the bike dead due to a lack of momentum. 29x3" tyres might help a bit here (better rollover), but whilst standing usually helps it's very difficult to do in gears less than ~20", and 23-26" is much more reasonable.

IME, with 26" wheels, 20x32 was quite useful (occasionally), but 15x26 and 15x34 were not, due to stalling out when the bike wouldn't roll over even small obstacles. At some point walking is more efficient, and less tiring both physically and mentally. There's also little or no speed difference, and a much reduced chance of hitting the deck! Once one gets below ~5km/h or 3mph walking becomes much more attractive...

On bitumen, gears below ~19-20" are rarely useful unless you're on a 25+% road in the UK, or else at altitude in the Himalayas. On dirt, ~16" can be useful on steep hardpack climbs, especially to get over water bars. However, some things just aren't really rideable unless perhaps you're a trials specialist.

In theory, one could have gears down to 15-16x52 with parts that have been commercially available, but 20x50 would be easier to get, and should be possible with double rings like say 30x20 and the widest range S-Ride rear derailleurs, but I have doubts about how useful a gear like 20/50x27 = 10.8" is going to be. YMMV.

Oh, and 4 chainwheels shift abominably and have serious chainline problems in case anyone was contemplating that option...

Later,

Stephen

[wood chuck]

I have a Microadaptor that came with a 20T Suntour (56 bcd) stainless ring. It helped me finish the Mt. Washington bicycle hill climb ride three times. Maybe Avid made two versions(?) Also, try Peter White for TA 56&58 rings.

[wood chuck]

OOPS!! I meant TA makes rings with 56&58 bcd. They have 20&22T.

[Brad]

Here you go.  https://www.ebay.com/itm/314091546279?hash=item492150a6a7:g:WAoAAOSwq6hfOylY&amdata=enc%3AAQAHAAAAoGQx%2BhhxYEMRnw1lZWjpobcyDgP4jwgVcrS9C3T0IcrNB%2BBNLmUWRiKyjRPoGccDyTueOk1GNoNkGuZqiEF6ECxacS5xSUVAZ9s1TEKpjDKisBpnzFm3hPjdNmB4wM5yyTRuY%2BjOiidwico7%2FVkkfgYwPmtC0A69f5n1%2FKs2lBkqs%2FYCoxmLsDewf9x8Rk%2Fhx9ntlwkU%2FehIDYyeyb%2BYfUs%3D%7Ctkp%3ABk9SR5a_3IX-YA

[Michael Wong]

I assume the OP wanted to keep their RD, which makes anything above a 40t tough. Also is a 50t  available in 10s?

 

I ride a 20/34x679mmX9s and a 27/42x668mmX11s and it's fine though I'm considering lower options as I age. My wife rides a 20/36x648mmX9s and she *does sometimes opt to walk, though often not.

If the OP wants to keep their current crank and RD, a 40t rear cog won't quite match the 20/34. And it's beyond drivetrain capacity but then so are most of these solutions. A low granny is a reasonable solution