Folding Bikes - At last.....my R20's got a straight chainline and a quiet chain tensioner

Just installed a 110mm UN72 BB on my R20 single speed, much better than the 127mm it had. I now have a straight chain line and guess what??...
The chain tensioner must now be happy 'cos it's decided to "SHUT UP" ;)

This SS is a temp project as I've got a new set of 451 rims with a Sachs 3x7 hub waiting to adorn this bike and the SS's 406 wheels will be converted back to a 7 spd into another R20 frame I'm building up. This 2nd bike will possibly have 2 chainrings 58/48 and Vbrakes, so I'm going to be busy.

I will post pics when they're finished....both will be BLACK and named "The Scarab 1 & 2" aptly suggested by LittlePixel.

pix pix pix!

pix pix pix!

OK then, firstly I take some pics with my El Cheapo digital picture box, then I down load them onto my laptop......then I.....I....??

Go to www.photobucket.com. Create an account. Upload the pictures. Go to your gallery, and under each picture is a drop down menu with different sorts of link to that picture. Copy the "IMG" code one (it'll be obvious), and paste it into your post on here. Bingo!

I hope this works, sorry if the quality is poor.

The Scarab R20 SS





I probably could use a 60t or bigger front ring when spinning along with a tailwind, but then coming home into the wind would be a real grind.

PS: Thank you Sammyboy for showing the way....

pics are out of focus.

why you use a chain tensioner?

good looking bike :D

pics are out of focus.

why you use a chain tensioner?

good looking bike :D

1: I know, that's what happens with an el Cheapo camera and a moronic photographer who is home for a week because he's ill.

2: Maybe I'm even more moronic at bike mechanics than I am at photography but, it seems when I didn't use a CT I couldn't get the chain length right. It was either too long and sloppy or too short and chronically tight, even with the length of the R20's dropouts for adjustment. Half links didn't help either because my chainline wasn't perfect so the 1/2 link was grinding to one side of the 14t rear cog as it traveled over it. It might work now with a better chainline, but as this is a temporary SS project I'll keep the CT.

3: The pics don't do it justice, in the flesh when it's powder coat colour Onyx Black catches the light the emerald green flecks look unreal. It is very nice to ride, fast, accurate and comfortable.

Lookin' goooood!
Twentys really suit a pair of Conti Grand Prix...

Lookin' goooood!
Twentys really suit a pair of Conti Grand Prix...

Thanks Huw.......just got an invite to my niece's wedding in Sept in the UK, hoping to come over, love to bring the Scarab for a ride......need to sell my 750cc motorcycle :(

1: I know, that's what happens with an el Cheapo camera and a moronic photographer who is home for a week because he's ill.

2: Maybe I'm even more moronic at bike mechanics than I am at photography but, it seems when I didn't use a CT I couldn't get the chain length right. It was either too long and sloppy or too short and chronically tight, even with the length of the R20's dropouts for adjustment. Half links didn't help either because my chainline wasn't perfect so the 1/2 link was grinding to one side of the 14t rear cog as it traveled over it. It might work now with a better chainline, but as this is a temporary SS project I'll keep the CT.

3: The pics don't do it justice, in the flesh when it's powder coat colour Onyx Black catches the light the emerald green flecks look unreal. It is very nice to ride, fast, accurate and comfortable.

I have discovered in my Twenty trials and tribulations that you need to use an odd number sprocket on the rear for the chain legnth to work. Mine came stock with a 44/15 I tried like hell to get a 16t on there but it was a nogo due to the chain issues you mentioned. Put a 17t and voila perfect fit. I find it hard to believe that it was engineered that way, probably more like dumb luck.

Aaron:)

Thanks Aaron,

That's interesting, I will have to find that spare Shimano 13t cog that's hiding somewhere in my shed and try that out.
My three Aussie R20s came with a 46/16, wonder why the difference?

Thanks Aaron,

That's interesting, I will have to find that spare Shimano 13t cog that's hiding somewhere in my shed and try that out.
My three Aussie R20s came with a 46/16, wonder why the difference?

Yours are fixed frames aren't they? The one I have, and the two more I have on the way:innocent: are all folders.

Aaron:)

Yours are fixed frames aren't they? The one I have, and the two more I have on the way:innocent: are all folders.

Aaron:)

I still don't understand why that should make a difference, maybe Aussie riders are stronger? ;) .....as in, strong in the legs....weak in the head.

nice !
are you fitting the gears later LOL
can I see folded picture?

nice !
are you fitting the gears later LOL
can I see folded picture?

Not sure whether you're teasing me, but......

I: The rear hub is a 9 spd converted to a SS, I'm hoping to make it 7 spd in the not too distant future.
If I was using a 7 spd cassette the chain when on the smallest gear would rub on the bike's frame, so I'm using 7 cogs from a 9 spd cassette, a spacer and a 9 spd chain because it's narrower...should work.
I've got an Alivio FD which is the only FD that fits the R20 frame, so I'm hoping it will work with 58/48.

2: This is a non folding frame....I like non folding frames, someone once questioned the point of a non folding SWB, my answer?.....very strong for aggressive riding and heavy touring.....not that there's anything wrong with R20 folding frames. :)

A lot of front mechs are multi fit these days.
With fiddly spacers and sticky backed plastic. They fit on 28.6mm, 31.8mm and 34mm
So theres a lot that will fit a 31.8mm seat tube.

I geuss you need a top swing mech. As the cross bar is in the way of the mech clamp of a conventional front mech.

Can the Alivio handle such a large chainring though?

My Marin Hawkhill has a 7 speed cassette with a spacer behind it. Looks like the previous owner has replaced the wheel.
Are you going to fit the spacer between the lockring and the small cog. Will the chain not scrape on it there.
What shifter are you going to use? Are you gonna use a 9 speed shifter.

I used to work at Halfords and they sold a Hybrid that had MTB rapid fire shifters for a triple chainset. But it had a double chainset. The owners would come in with gear shift trouble as they kept on clicking for a gear that wasnt there. We would set it to shift on 2 to 3. So as to not strain the shifter gubbins.

Not sure whether you're teasing me, but......


I should have noticed the lack of a hinge!

People mention putting on 60t chainrings to gear up. I have nether seen a reasonably priced one have you?

Ive not seen a cheap 60 tooth chainring.
I did get a Campag 56 tooth chainring from ebay for £5, I think.
Not used it yet.
Using my Campag stuff on a Raleigh Flyer road bike.

I have seen a man on a recumbent site that makes his own chainrings.

A lot of front mechs are multi fit these days.
With fiddly spacers and sticky backed plastic. They fit on 28.6mm, 31.8mm and 34mm
So theres a lot that will fit a 31.8mm seat tube.

I geuss you need a top swing mech. As the cross bar is in the way of the mech clamp of a conventional front mech.

1: Can the Alivio handle such a large chainring though?

My Marin Hawkhill has a 7 speed cassette with a spacer behind it. Looks like the previous owner has replaced the wheel.
2a: Are you going to fit the spacer between the lockring and the small cog.
2b: Will the chain not scrape on it there.
3:What shifter are you going to use?
4: Are you gonna use a 9 speed shifter.

I used to work at Halfords and they sold a Hybrid that had MTB rapid fire shifters for a triple chainset. But it had a double chainset. The owners would come in with gear shift trouble as they kept on clicking for a gear that wasnt there. We would set it to shift on 2 to 3. So as to not strain the shifter gubbins.

Griftereck,

1: Not sure if the Alivio will handle the 58t, but it wouldn't take much work to lengthen the cage to suit.

2a: Yes.
2b: And not sure, I think it's a case of try and see, then work out a solution.

3: I have STI 7 & 9 spds shifters, bar end shifters, grip shifters and triggers, what would you suggest?

4: If I use a 7x 9 spd cog set up and chain do I really need 9 spd shifters? Would 7 spd shifters work?
I'm not sure what Sheldon Brown would say.

Cheers
Stevegor

the spacing on a 7speed and a 9 speed are different.
so I think you should use 9 speed shifters with whats left of your 9 speed block.

I geuss you could fiddle with what side the gear cable goes onto the clamp bolt.
I seen a MTB magazine ages ago have a feature on mixing up different speed gears and shifters.
Think theres some websites as well that go through it too.

OK, thanks,

Might take some time to complete as I want to do the Sachs 3x7 in the 451 R20 first.

Keep me informed of your travel plans - would be great for our Twennies to meet!
(But getting it on a plane is probably a massive pain so don't sweat it if you can't...)

Keep me informed of your travel plans - would be great for our Twennies to meet!
(But getting it on a plane is probably a massive pain so don't sweat it if you can't...)

Will do, if I don't bring it this time, I have a grand plan of touring the UK on my R20 one day.....

Hmmm, I wonder if your R20 will look down it's front fender at my "Colonial" R20's lower-class appearance and say, in a superior upper class trill, "Oh, you're one of those CONVICT poor relations...aren't you?" I hope not.

All Twenties are created equal so there'll be none of that silly business. It might snicker at your tensioner though... ;)

All Twenties are created equal so there'll be none of that silly business. It might snicker at your tensioner though... ;)

Wonder what they would think of mine with alloy rims, AG hub and LED tail light:eek::innocent: My plan on this one was upgrades but keep it looking pretty much stock.:D

Aaron:)

Hey!!! quit lookin' at my CT

I've just found the yin to the Scarab's Yang; White Twenty (I dub her the 'Pale Rider')
http://moralinefree.blogspot.com/2009/06/after-grips-and-adjustments_22.html

I've just found the yin to the Scarab's Yang; White Twenty (I dub her the 'Pale Rider')
http://moralinefree.blogspot.com/2009/06/after-grips-and-adjustments_22.html

Very nice, now if these two R20s ever met they could have........grey RSW16 babies. :roflmao2:

Very nice, now if these two R20s ever met they could have........grey RSW16 babies. :roflmao2:

Dibs on adoptions...:lol:

Aaron:)

Call me mad if you like, but I'm seriously thinkin' about doing a 100 mile ride on this R20 SS this coming Saturday....lots of hills and rough roads, am I mad?

I have discovered in my Twenty trials and tribulations that you need to use an odd number sprocket on the rear for the chain legnth to work. Mine came stock with a 44/15 I tried like hell to get a 16t on there but it was a nogo due to the chain issues you mentioned. Put a 17t and voila perfect fit. I find it hard to believe that it was engineered that way, probably more like dumb luck.

Aaron:) Two words; "Half Link"

Call me mad if you like, but I'm seriously thinkin' about doing a 100 mile ride on this R20 SS this coming Saturday....lots of hills and rough roads, am I mad?Not sure, but if your relatives ever try to have you committed, I wouldn't mention having done so at your hearing.

Come to think of it, sinking a lot of time and $$$ into a heavy 30+ y/o bike doesn't make a lot of sense to people outside this little asylum of ours.

Two words; "Half Link"

I thought about that...but didn't have one handy.

Aaron:)