Linear Front Derailleur Mount Query.

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a.twiddler

Veteran
I have been pondering the possibilities of resuscitating the front derailleur on my Linear at some time in the future. It has the frame mounting block in place, but it is missing the short tube to which the front derailleur attaches On measuring the circular groove in the top of the block it seems to be about 1". Could some obliging Linear owner out there who has one fitted measure the diameter and length of their mounting tube and let me know? I could then find a suitable bit of tube and possibly hold it in place with a threadless steerer cap and bolt. Perhaps a photo of the existing set up could be helpful.

That would only leave me to find a Suntour X-1 front changer, or an equivalent, to match the Suntour 52-38-28 triple that is on it, and a cable stop. My bits box is heaving with odd shifters and spare cables.

I don't actually need 63 gears, but sometimes it could be convenient to jump onto the small ring to get up an unexpectedly steep or long climb. Also by occasionally shifting chainrings it could help to even out wear on the rear cassette. I have a feeling that in the lowest of the low gears available it's not possible to actually ride that slow without falling over, and similarly it's a bit ambitious to expect these legs to push the immense top gear available. Still, if you have got the potential facilities, why not make them work? Normal business would continue between the Sachs hub gear and the 7 speed cassette. but it's nice to have something in reserve. Also, I just can't leave things alone, and like to experiment.
 
The box section "I" beam on the Linear is wider than the norm ? If the bottom bracket is none original (Linear OEM is extra wide) . You may have issues fine tuning the mech to allow all three rings to function . The control cable run has quite tortuous routing ...so always buy high quality inner and outer cables . If you still need images ....ping me a message with your Email address .
 
Could you use one of the MTB front mechs that are secured by the bottom bracket shell, ie original Shimano e-type? At least it would be in the right place relative to the chainrings. For example:

https://www.hargrovescycles.co.uk/c...MIx4Gz2fTk7QIVENnVCh3mnQmoEAQYAyABEgLydvD_BwE

although this is top of the range they made them all the way down to Altus models. You would only have to think about cabling and stops. Probably you are going to need smaller rings, but with a 3 speed hub at the back you’re unlikely to need a 52T ring unless you regularly ride down vertical drop offs or have massive thighs...
 
Only 56 gears here on my ICE Sprint ....... :sad:

I've found that having ultra high gears means I don't spin out going downhill before I decide if I need to freewheel.
Keeping my most efficient cadence downhill as well as on the flat/uphill saves me energy in the long run.
Being more efficient means it's easier to go for longer.
Plus I love the ability to pedal slowly downhill at 40 mph ........ :whistle:

YMMV .......... ^_^
 
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a.twiddler

a.twiddler

Veteran
The reason I mentioned the Sun Tour X-1 front derailleur is that is what's on the photos I've seen of Iowa Linears with the corresponding X-1 triple chainset which is on mine, which could reduce the likelihood of incompatibility. As @Mr Magoo suggests, the BB is wide, but then as @recumbentpanda observed, the mounting point on the derailleur block is well offset to the right.

From searches on the net it seems that X-1 FDs come with clamps to fit 31.8 or 28.6mm tubing, maybe others too. If the mounting point on the derailleur block can be persuaded to take a 28.6mm tube then a section of seat pin of that diameter would do the job. The suggestion for using a Shimano e-type FD would give a neat solution but it would be nice to stick with the original chainset, as it's not very worn, and a used or NOS X-1 FD won't break the bank. Suggestions for alternative triple FDs which can cope with the 28-52 would be welcome. Perhaps even top pull FDs which could allow a more generous curve of cable run from above, making the routing less tortuous (though I imagine that Linear used the bottom pull set up for a reason).

It ought to be possible to make the triple changer work without too much difficulty. If there are any alignment issues which can't be simply overcome, it isn't the end of the world to revert to manually changing the chain on to another chainring as it is now, though less convenient.
 
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a.twiddler

a.twiddler

Veteran
Update.
I got the bits together and had a go at setting up the triple on the front. After a lot of experimentation I have a feeling that my "refurbished" X-1 may be a little distorted as it will change OK when set up on small-medium or medium-large but not on all 3. The changer does not have any issues with the frame width or reach. I don't have another X-1 to compare it with. On reflection, did I need such a large chainring?

I don’t see me using a 150 inch gear any time soon, and the middle ring gives 111” with the hub gear. Initially I tried to set it up without using the big ring via the limit stops but it “just” needed the changer to overlap the big ring, causing some rubbing. I got some washers out of my nuts and bolts box and just took the big ring off. I noticed that it had “Stronglight” embossed on it. Using the washers I was able to just use the smaller rings and also fit the changer lower down. It now changes easily and it can be trimmed to run silently. Due to the long chain all the gears are usable without pulling the chain across at an angle. I could shorten the chain to reduce the sag but as it is practically running as it was before I will give it a few good runs before I decide what to do about it. Once it’s shortened it will not be easy to go back to the original set up. It may be that the convenience of having 42 easily available gears will outweigh the potential of having 63 manual ones at hand.

Further update.
Following a 26 mile test run I can confirm that the new set up works really well, far better than I had expected. The gear range is now from around 20" to around 111", previously around 28" to 111" which is a useful improvement and very noticeable. I include a photo if anyone might be able to suggest any obvious adjustments.

575358
 
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a.twiddler

a.twiddler

Veteran
An update.
27/2/21
I was going to give the set up a good work out today via Wettenhall/Oulton Park/Cotebrook/Delamere/Kingsley/Acton Bridge/ Weaverham/Northwich/Moulton/Meadowbank/Winsford and all went well until I got to Kingsley. I can’t fault the double ring set up which works fine, apart from a slight creaking. The chainring bolts might benefit from tightening or perhaps new dedicated bolts and washers. Anyhow, I had just climbed up from Hatchmere and was on the downhill to Kingsley when the chain started binding. I eased off and it freed but soon afterwards started binding again. I stopped and saw that the rear derailleur arm had curled up on itself and one of the jockey wheels had unscrewed itself and fallen off. Fortunately it was lying in the road but there was no sign of the side plates, bush, or bolt. I picked it up and went back to the bike. I spotted that the bolt was protruding from the derailleur arm so I put the jockey wheel back in place and screwed the bolt in to stop it getting lost. I decided to shorten the chain and use it as a 3 speed to get home. I kept the removed links to be able to reinstate the chain length later.

On the way home I thought that I’d had a bit of target fixation on the front changer. The rear one had worked fine since I bought the bike last year and I’d had no reason to think that it was going to bite me in the behind. Just goes to show, you need to check everything from time to time. (See “my ride today” for 27/2/21).

The bike ran well as a 3 speed as I set it up to run on the smaller front sprocket and 5th on the rear cluster. I did walk up one pitch but generally the gears being on the lowish side worked surprisingly well.

28/2/21
I found a set of unused shimano pulley wheels in my bits box, though they were plain plastic, complete with with side plates and bushes. The pulley that fell off had an integral steel bush. It was actually in good condition. The other pulley looked worn with a chip out of it so I replaced that as it was a similar pattern to my spares, and fitted new side plates and bushes. I checked the pulley bolt threads for wear and they seemed OK. I put plenty of threadlock on them then greased them up on re fitting. I measured up the chain and refitted the links I had taken out before setting the length for the double ring set up. Everything worked well on big/big and small/small on the stand and I was looking forward to a test ride. I was pleased that I’d managed to restore it back to working order so easily and at no cost.

I just thought I’d give the chainring bolts a tweak before going in for a drink. I got round four of them OK then just as I was tweaking the last one, tchink! It broke. A fine selection of expletives was brought out before being put away again. Mrs Twiddler appeared round the side of the shed, gave me a sour look then disappeared.

I managed to order a single set and a double set and some washers from SJS cycles.

11/3/21
I wasn’t sure whether the single chainring bolt set would have enough thread which is why I also ordered a double and some washers but fortunately the single set was long enough. I took the small inner ring off to fit the outer (former middle ring) and it all went together easily.
Beware-kitchen table mechanic at work!
579527

The other side.
579528

The extra bolts and washers went into my bits box in case I want to make it a triple at some time, and the bike is all together now waiting for a test ride. The chainrings certainly look a lot neater now.
579529

It would probably all benefit from a good clean.

15/3/21
A bit windy but not actually raining this afternoon. The weather has been so rotten recently that I just needed to get out. Needed to post a letter so went out for a short test run. All 42 gears change smoothly. A nominal range of 20" to 111 ish inches. There is absolutely no creaking from the front rings. Middle gear on the rear hub is direct drive, so "ought" to save energy if used as the “normal” gear to work the rest around. Just use the hub for super high or super low. I try to remember to park it in the garage in high so it allows the spring to be in low tension. Ideally the derailleur should be left in high too, and the front changer in low. Does anyone actually do that?

Now for a proper ride!

5:15 pm while taking the car for a wash spotted a recumbent trike waiting at the town centre lights. Rider had an inane grin on his face which I suspect is what I look like when I’m out on my two wheeler. An occupational hazard of being a ‘bent rider I believe.
 
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