Double singlespeed?

[ColinJ]

I just looked up the widths of different speed chains... The 8-speed chain I had fitted is about 1 mm wider than the 10-speed chain that the original donor cassettes were designed for. No wonder there is rubbing!

I have a new 10-speed chain. I'll put that on and either give my 8-speed chains to a mate to use on his singlespeed road bike, or keep them to use on my singlespeed turbo trainer bike. (If the latter, then they would probably outlast me because I barely use the turbo trainer now.)

There is some slack in the gear cable so I have to turn the shifter lever through about 30 degrees from its downmost position before it starts the shift off the 12 tooth sprocket. I'll do the bar tape first because I want to loosen the shifter body to tuck the tape in under it. Once that has been tidied, I will take up the slack in the cable. Oh yes - the shifter does pull enough cable for my 6 sprockets. I'm not sure that it would have been able to do a full 10-speed cassette rather than my edited highlights version though.

I'll get back to work on it once my brunch has gone down. The weather is not bad here today so it would be good to get a test ride in later. Rain is forecast for tomorrow...

 

[ColinJ]

I have a new 10-speed chain. I'll put that on and either give my 8-speed chains to a mate to use on his singlespeed road bike, or keep them to use on my singlespeed turbo trainer bike. (If the latter, then they would probably outlast me because I barely use the turbo trainer now.)

The 10-speed chain is a lot quieter; it was a silly mistake to have put the 8-speed chain on. I'll give one of my 8-speed chains to my pal, and keep the other as a spare for my turbo bike.

I'll get back to work on it once my brunch has gone down. The weather is not bad here today so it would be good to get a test ride in later. Rain is forecast for tomorrow...

Unexpected visitors put a stop to that. Hopefully I will get it finished today (Wednesday).

 

[ColinJ]

I finally finished upgrading the bike!

The gears were shifting really well on the stand. The transmission is at least 50% quieter than it was on the bike in singlespeed mode. I haven't ridden the now-geared bike yet. It looks like a thunderstorm is brewing here so I am having a coffee break instead. If things clear up this evening I'll do a lumpy little test ride then and take some photos of the bike.

The huge-range MTB rear derailleur is overkill for this project (only having to change in the range between a 12 tooth sprocket and a 29), but it is a quality bit of kit which was sitting around doing nothing in my spares box. It is good to find a use for it. I really liked the price that I paid for it - £0.00... it was donated to me by my cousin when he upgraded his MTB from the original 9-speed groupset!

The Dura Ace friction shifter is very nice. I like the fact that it is tucked away on the LH bar end. When riding in singlespeed mode I will almost forget that it is there and so be less tempted to wimp out into one of my 2 climbing gears!

I have put a rearview mirror in the RH bar end. When I first took it out of the box it looked absolutely awful. Serves me right for being a cheapskate and buying a pair of mirrors for £5.99? (The price has gone up a little since then.) Then a mate pointed out to me that there was a cloudy protective plastic film over the mirror. It sounds really stupid (and it IS ) but I thought that the plastic label warning of a protective plastic film WAS itself the plastic film! I don't know how long the mirror will last before I accidentally snap it off, or some idiot does it deliberately when I leave the bike locked up when shopping.

I shouldn't have bought the same fragile bar tape as before... I had forgotten that my usual ham-fisted bar-taping technique does not work with tape that self-destructs when being unwound! It can take me 5 or 6 attempts to wrap a bar neatly. I had just one go then, and messed it up! It isn't the worst wrapping job ever but it would be generous to give it 6/10. Never mind - the double-wrapped bars should be pretty comfortable on our rough local road surfaces.

Ride report and pics anon!

 

[Venod]

I shouldn't have bought the same fragile bar tape as before..

I refurbished one of the grandsons bikes, I sent for some cheap tape from China, it took ages to arrive and the bike was ready minus the tape, so I put some on his bike from the LB shop, knowing I could make use of the China tape somewhere down the line, well I just used it, the worst tape I have ever fitted, very fragile tears if you look at it, so some Cannondale knurled stuff ordered at a discount price from Cycle Store.

 

[ColinJ]

And I thought £7-8 was a lot for bar tape... The tapes at Cycle Store look really good but this is a cheapo bike project so I would not pay that much!

Right - I am off out on my test ride. I will report back later.

 

[ColinJ]

Test ride completed...

I was right about forgetting about a gear shifter being tucked away on the left bar end. I had left the bike in 42/12 which is a much higher gear than the 42/15 (roughly equal to my old 52/19 singlespeed gear). It took me a while to realise why pedalling felt like harder work than usual!

I shifted into the 42/15 and went to ride up a short ramp. The chain slipped! At first I thought that the old 15 sprocket that I had used must be more worn than it had looked, but then I remembered that friction shifters do not work like indexed shifters. I hadn't used a friction shifter for 30 years, so it isn't surprising that I had forgotten about trimming the lever position - listening for the clicking sound as the chain tries to go up or down to an adjacent sprocket, and taking action to stop it! The trouble is - my hearing isn't what it was 30 years ago, and neither is the amount of traffic... I was finding it hard to hear what the gears were doing so I was having to go more by feel. I didn't get any more slippage so I am hoping that it was just a trimming issue.

I stuck in the 42/15 as far as Summit, which is a gentle rise up from Todmorden on the A6033 towards Littleborough. After that I used to spin out on the gentle descent to Littleborough so I would end up going down at 25-34 kmph. Today I just whacked it into the 42/12 and did a more satisfying 30-40 kmph.

I met @Littgull in Littleborough and we went to the new RSPCA cafe near Hollingworth Lake to catch up on news since our last get-together.

We had planned to sit outside but we didn't have any sunshine and a chilly wind was blowing so we went inside. I didn't have a lock for my bike so I sat near the door and kept a close eye on my bike. At one point I looked up and saw a couple allow their dog to drag them over to my bike so he could piss over it... I kid you not! I got a rush of blood to the head and was going to go outside and challenge them but it was too late to stop the dog. I thought better of it. No point in spoiling a nice afternoon. At least he managed to miss my pannier!

Anyway, back to the bike! When we came out of the cafe I took some photos for y'all...

Dura Ace bar end shifter and Col's iffy bar tape wrapping:

Skinny rack, pannier bought from @Vantage, and DIY mudguard made from length of old tyre!

6-speed bike!

The red circle highlights some of the dog piss! You can see my DIY 12/13/14/15/23/29 cassette. The MTB mech is clearly much longer then it needs to be but that avoids any extreme chain angles. I really like the relaxed cable routing on those mechs - much less potential for excess friction than having to use a big arc of cable. Yes - despite being cleaned a week ago, the bike is mucky again and needs more TLC!

Bar end mirror photo-bombed by a prowling @Littgull (and more iffy bar taping)!

I added a couple of small hills into my return route and used my 23 and 29 on them even though I could (just) have managed on the 15. I wanted to check that those other gears worked properly - they did!

Verdict: An interesting and worthwhile project! I now have a more versatile bike which I can use over much more varied terrain, while still doing most of my riding on it in a 74 inch gear. (I normally use the metric units but I have never seen any cyclist refer to an xx cm gear! )

 

[Dogtrousers]

. (I normally use the metric units but I have never seen any cyclist refer to an xx cm gear! )

I think that in France they use développement which is the forward distance (in metres) that the bike moves with one turn of the pedals.

 

[ColinJ]

I think that in France they use développement which is the forward distance (in metres) that the bike moves with one turn of the pedals.

Aha!

Or, as the Americans would say... 'Meters development'!

 

[ColinJ]

I shifted into the 42/15 and went to ride up a short ramp. The chain slipped! At first I thought that the old 15 sprocket that I had used must be more worn than it had looked, but then I remembered that friction shifters do not work like indexed shifters. I hadn't used a friction shifter for 30 years, so it isn't surprising that I had forgotten about trimming the lever position - listening for the clicking sound as the chain tries to go up or down to an adjacent sprocket, and taking action to stop it! The trouble is - my hearing isn't what it was 30 years ago, and neither is the amount of traffic... I was finding it hard to hear what the gears were doing so I was having to go more by feel. I didn't get any more slippage so I am hoping that it was just a trimming issue.

I have had the problem happen twice more but only under maximum pedalling effort (standing to power up a short, steep ramp). The gear had definitely been properly selected on those two occasions so it does seem to be due to a worn 15-tooth sprocket. It isn't really surprising because that would have been one of the more often used sprockets on the old cassette that it was removed from. I have several more old sprockets that I can try instead. I'll do that in a couple of weeks time when I get back from my coming holiday in Devon.

The bike is otherwise working really well.

 

[ColinJ]

I took a closer look at a photo that I had taken of the collection of old sprockets that I used to make this 6-speed cassette. Er, yes, some of those 15s are pretty worn!

It's a new chain so I really should have looked more carefully at what sprocket I was using. It was one of those labelled 1-5. It is almost good enough, so unless I just happened to have selected the best of those worn 15s, one of the others would probably be okay until the chain wears enough to be a better fit.

I'll make sure that I pick the best one when I take the cassette to bits later in the month.

 

[ColinJ]

I put one of those other 15 tooth sprockets on this evening. While doing that I discovered that I really needed a thin spacer adding behind the cassette because the lockring was hardly biting on the serrated edge of the 12 tooth sprocket. What I needed was just under half the thickness of the spare spacers that I had. One flash of inspiration later, I'd used an old 13 tooth sprocket as a thin spacer and that fixed the problem.

I went out and did a 9 km test ride with a few steep ramps on it. I gingerly stood up to climb them in the 15 and the chain didn't slip. I won't feel completely confident that the problem is fixed until I have done another few rides though.

 

[Chris S]

Are there any photos of the double-singlespeed drivetrain?

 

[ColinJ]

Are there any photos of the double-singlespeed drivetrain?

Er, yes... Earlier in the thread, upside down, HERE!

(The 3rd sprocket that you can see was not used for riding in that incarnation. It was only there to tighten the lockring against.)

Last night I just rode the bike as if singlespeed. I can manage the climbs on that route in the 42/15 so I left it in that gear. I had toyed with returning by a different route which has a 15% climb. If I had gone that way I would have used the 42/29.

 

[Dogtrousers]

I've got a book somewhere on the history of the derailleur. It has pictures of all kinds of strange designs that they used way back before they finally figured out the best method.

Your photos remind me of that

 

[Mike_P]

I've got a book somewhere on the history of the derailleur. It has pictures of all kinds of strange designs that they used way back before they finally figured out the best method.

..that is currently known of