Double singlespeed?

[ColinJ]

I am still planning to do this conversion and have been looking at it again over the past few days...

I was going to use an old Campagnolo Athena derailleur but I noticed that the body is cracked where the mounting bolt passes through. It would probably be okay for a while but I don't fancy being 80 km out on a ride and have the derailleur suddenly snap off!

I had a look through my junk box and found an ancient and very tatty-looking Campagnolo Nuovo Record derailleur. I thought I would clean it to get a better idea of what state it is in. It turned out to be much better than expected! The jockey wheels need replacing so I have ordered some.

This photo shows the derailleur now but I have included an untouched jockey wheel to give you an idea of how the whole thing looked an hour ago!

It might struggle shifting to a 29/30 tooth sprocket but I reckon that there will be a way to get it to work.

I have found hardware that would let me fix my Campagnolo friction shifter to the seat tube but that would then leave me with the problem of how to route the cable to the derailleur. I would have to fit something else to the bottom of the seat tube to turn the cable towards the back of the bike. I don't think it would work by wrapping it round under the bottom bracket, though it might?

I think the ideal solution would be to use a bar-end friction shifter and route the cable normally but I don't want to spend much cash getting hold of one.

If I do this conversion, I want to keep my perfect chainline for the 42/15 gear that I will do most of my riding in. That means that I would have to put a 4th sprocket in between the 12 and the 15, so the gearing would end up being a 42 tooth chainring, with a 29 or 30 tooth sprocket for climbs steeper than 10% (or with long stretches at 8-10%), a 15 tooth sprocket for normal use, a 13 or 14 tooth 'filler' sprocket which probably would barely get used, and a 12 tooth sprocket for use when I was spinning too fast on 42-15 (speeds greater than around 32 km/hr).

 

[Dogtrousers]

I think this project is completely bonkers.

I fully approve.

 

[ColinJ]

I thought that having a ridiculously awkward gear change would encourage me to stick to one gear most of the time.

Which it DID...

... by deterring me from doing many rides that required that gear change!

It was really nice having the one extra climbing gear though because I was able to do some nice rides on the bike without having to take long mid-ride walks. (I probably discussed this earlier in the thread but can't be bothered to check!)

What I would really like is to have clunky gear shifting which required me to dismount and nurse the chain into the other gear(s). That would encourage me to stick in my favourite gear and remind me that the other gear(s) is/are to be avoided when possible, but would let me change gear in seconds rather than minutes when I absolutely had to, and would not involve me getting my hands dirty.

I am very happy to use all 30 gears on tough hilly rides on my CAAD5, but the rides on this bike are a different experience and I'd like to keep it that way. There is something satisfying in getting up a stiff climb when overgeared. I just don't want to be overgeared to the point where I have to walk. (Yes, I know that I could just not change gear on a multi-geared bike but that would do my head in - struggling because you don't have an option is one thing; struggling because you are just being stubborn is another! )

 

[ColinJ]

I am cracking on with it...

The new jockey wheels came today so I'll reassemble the derailleur later. It would be nice to use that one but it won't really matter if it turns out not to cope with the 29/30 sprocket because I'd forgotten that I had a very nice XTR rear mech stashed away. I'll put it on my MTB and could use the old LX mech from that on this road bike project.

I decided that I would not mess about with a 'clunky' shifter! I found a nice Dura Ace bar end shifter on eBay and my bid for that has just been accepted. It is a LH shifter but that won't matter in this application. (I may put a mirror in the RH bar end anyway.)

Now I need to order the gear cabling.

I don't like the traditional way that people route cables from bar end shifters out from mid-bar tape on dropped handlebars. If possible I will put the cable under the tape right up to the end of it, alongside the brake cable.

I have a metric century coming up on the 29th which I want to ride on this bike. There are no troublesome hills on that route so I will probably delay the conversion until after that, in case I get something wrong! I would rather have any problems surface on a local ride rather than on a forum ride with several other CycleChatters, many kms/miles from base.

 

[ColinJ]

Now I need to order the gear cabling.

I found an outer + ferrules in the same box as the XTR mech. I might have an inner gear cable somewhere but I've ordered one anyway - it won't hurt to have a spare.

I need a cable guide for under the bottom bracket. I have a redundant one on my turbo trainer bike which has been converted to singlespeed so I'll pinch that.

When this conversion has been done, there will be a BIG 15 to 29 (or 30) step between the higher 2 gears. It will be interesting to see how well THAT works!

 

[ColinJ]

I might have an inner gear cable somewhere but I've ordered one anyway - it won't hurt to have a spare.

Ha - a spare spare cable... I hadn't noticed that a cable is included with the shifter!

 

[ColinJ]

I did 110 km on the bike yesterday in my current 52/19 gear but today was time to crack on with the conversion.

I started this afternoon but 2 problems stopped me proceeding...

Problem #1: My (only!) 1 year old bar tape ripped multiple times when I was removing it - VERY annoying! I have reused less expensive tape multiple times in the past. I think I will order cheaper tape to replace it.

Problem #2: More seriously - I have just discovered that the downtube boss for the gear cable has a piece of outer gear cable corroded into it and hacked off by a previous owner. I have tried various ways to remove it but it won't budge so I think that I will have to drill it out. That will have to wait until tomorrow because I have a guest to feed and then we will be watching TV.

 

[simongt]

Fixie one way around, plus no disc brake as a result (if you care)

Ref an earlier post on the subject, I've now seen at least three disc braked fixies around Norwich.
Musty be getting popular - !

 

[ColinJ]

I have bought more of the same bar tape, because I like it! I'll use one roll to replace the torn tape and keep the second roll as a spare in case of future damage.

The old chain was worn and would have been too short so I have a new chain ready to use.

I decided to use the XTR MTB rear mech. Bit of a cock up on the sprocket front though... I left off the sprockets that I didn't want to fit and shunted the 29 across to where...

... it collides with the rear mech! I'm going to have to move the sprockets as far inwards as necessary to deal with that problem. After doing that, my perfect chain line will be lost. I could move the chainring to the inner position which will help a little. It will look a bit odd though. Then the 12 tooth will be too far from the other sprockets to use. Unless I put another 12 on as well, next to them...

I have solved the ferrule problem by using one of these to feed the cable through the small hole available...

I know that many of you think that this project is very odd. You will think it even odder that while this bike is in bits I have been riding my CAAD 5 using only 2 of its 30 gears, to replicate the 2 main gears that I will be using after this conversion!

 

[ColinJ]

I got gears, they're multiplying
And I'm losing control
But the power I'll be supplying
I'm not electrifying...!

I have been enjoying playing about with the bike but I want to get it back on the road now, so I have been getting stuck in on it. I've just stopped for a coffee break.

A reminder of how the project has developed thus far...

I built a cheap singlespeed bike a few years ago when I was very hard up. I used donated parts plus various old bits that I had lying around. The total cost at the time was around £80. I thought I would mainly use the bike for nipping up and down the local valley roads to visit friends or going to the shops. As a cheap DIY bike, it is the only one I own that I don't worry about leaving outside shops.

To my surprise though, I actually enjoyed riding the bike. I started doing more challenging rides on it than I ever expected. I have taken it to Cheshire and the Vale of York and done multiple 100 mile and 100 km rides in those flattish areas.

Then I retired. I starting funnelling some of my pension into an upgrade fund for the bike. I put a nice rack on it, new brake levers, bars. stem, and bar tape. I bumped into a former colleague and discovered that he had an unused white Planet X saddle, the type that I like to put on all of my bikes, so now it is sporting that too.

But... I could only get up moderate hills on the bike, which rather limited where I could use it. I needed a bailout gear for the steeper stuff!

And so the 'Dinglespeed' was born. 2 gears... 52/19 for nearly everything; 42/29 for the hills that I could not ride up in 52/19! It worked. The only problem was, getting off the bike and shifting the chain by hand was messy and annoying. I needed to invent a mechanical gear shifting system. And then I remembered that those amazing devices already existed! I decided to add a rear derailleur and a shifter. I already had a mech and I bought a bar end shifter on eBay.

So, I would use one ring and end up with a 2-speed bike with a convenient shifter to do the rear shifting. No more dismounting at the foot of steep hills and swearing at innocent pedestrians as I dropped the chain yet again and got my hands covered in oil, which I then transferred to my nice white saddle!

I would use the 42 tooth chainring with a 15 tooth sprocket for my main gear. That is only about a 2% higher ratio than my current 52/19.

Ah, but I also had a 12 tooth sprocket fitted for the cassette lock ring to tighten against. (The first incarnation of the bike just had a bunch of spacers to tighten against and the lock ring came loose on a 100 mile forum ride over the Humber Bridge.) I hadn't been using the 12 for riding purposes, but now that I was fitting a derailleur I might as well. Ok, the 2-speed would become a 3-speed.

What about my carefully perfected chain line? Right, I'll add a 14 tooth sprocket to keep the 15 in the ideal place! It would become a 4-speed bike.

I put it together that way and found that the 29 tooth sprocket was far too close to the body of the derailleur and the chain was getting jammed. What's more, the shift from the 15 to the 29 was too big a jump. I needed a filler gear - a 23. A 5-speed bike!

Still jamming... I added a 13 tooth sprocket. A 6-speed bike!

I have a sneaky suspicion that I might need to insert one more cog to get this to work nicely, but that can be determined on a test ride.

The thing concerning me now is whether the bar end shifter will pull enough cable to move the mountain bike derailleur by that many sprockets. (I have been moving the mech cage by hand because I haven't installed the shifter yet.) If the worst comes to the worst, I would convert back to 4-speed, using 13, 15, 23 and 29 tooth sprockets.

If you have stuck with me this far, you no doubt will be thinking that I have completely abandoned the original singlespeed concept. Not true! 42/15 is a very nice gear for 95+% of my riding on anything other than hilly routes. A 42/23 gear would be too low most of the time so I would rarely use it. There will be some hills that I can't get up in 42/15 which I could do in 42/23, and sometimes I would need the 42/29. I won't be heading out on this bike even after conversion to tackle climbs of 20+%. I have other bikes with lots of gears for those!

Back to work...

 

[Dogtrousers]

Pictures are needed.

 

[ColinJ]

Pictures are needed.

I will definitely take some pics once I have finished.

The latest progress...

• I adjusted the rear mech endstops to stop the chain over-shifting and falling off the cogs.
• I took a pair of links out of the chain. (I had deliberately cut it 'long' with a view to doing that once I saw how it shifted.)
• The upper jockey wheel was way too close to the cogs but there was not enough adjustment in the 'B-screw'*** to sort the problem out. Fortunately, I am a hoarder of old bike bits and other mechanical stuff. It took me about 5 minutes to find a screw 50% longer and with the correct thread. Carefully adjusting that stopped the rumbling sound from the transmission.
• I used an 8-speed chain that I had in stock for the singlespeed but I think the spacers that I had used for my DIY cassette might be from a 10-speed cassette which means that there isn't really quite enough room between the sprockets. The setup is working, but slightly noisier than it should be. I am hard of hearing so it won't really bother me on the road, but I will put a 10-speed chain on after I run out of 8-speed chains. (I think that I have another unused one somewhere and I don't have any 8-speed bikes so I might as well use it on this one!)
• I put a cable tie round that gear cable ferrule just to take strain off it since it doesn't actually fit properly into the downtube boss.
• I am just about to connect the shifter to the gear cable. I have been testing the shifts when pushing the derailleur cage in by hand. All seems to be ok so far.

If the shifter works well I will double-wrap bar tape over the cables on that side of the handlebar to match the other side. I am using a LH bar end friction shifter. Technically that is on the wrong side of the bar but it should work ok. It gives a better line for the gear cable outer and I am thinking of putting a rearview mirror in the RH bar end anyway.

If all goes well, I will finish the job tomorrow and go for a test ride in the evening.


*** Or whatever Shimano call them these days!

 

[ColinJ]

I am just about to connect the shifter to the gear cable. I have been testing the shifts when pushing the derailleur cage in by hand. All seems to be ok so far.

The friction shifter is working very nicely!

I'll do the bar tape tomorrow. Strictly speaking - later today!

 

[Dogtrousers]

I got gears, they're multiplying
And I'm losing control
But the power I'll be supplying
I'm not electrifying...!

I think you should seriously consider converting this to electrically powered shifting. I think it would fit in well with the project. I'm imagining something made out of sewing machine parts, powered by a motorbike battery duck taped to the seat post.

 

[Deleted member 1258]

I think you should seriously consider converting this to electrically powered shifting. I think it would fit in well with the project. I'm imagining something made out of sewing machine parts, powered by a motorbike battery duck taped to the seat post.

Sounds like you've been talking to Heath Robinson, interesting idea though.