Freewheel removal U plus 2 trailer

[Jdsk]

Would he do a copy?

Please let me think about that.

You can certainly have my specs.

Jonathan

[home]

To quote myself ...

The usual problem of kids' crank arms being too long is the first to be fixed. The originals are are both 150mm, and made out of chromed steel, which is too long. Working on the usual "10% of height rule", average 6 year olds needs about 125 to 130 mm cranks and average 10 year olds will ride 145 to 150mm cranks.

I'm guessing that crank shortening, and the benefits of, is something that's been discussed on this forum elsewhere. I'm a big fan. How to tell if your kids need it? Watching them cycle and see if their knees are coming up too high, or their pelvis is having rock up & down to reach.

Setting up a tandem with nice alloy cranksets quickly becomes really expensively, perhaps even moreso when doing so for kids.

SJS Cycles (for Thorn) are one of the few places that sell them but mostly they appear to be clearing out old stock. If you love your kids that much, or at least love your bling, then stock up whenever they have any, and soon because all prices are rising, but you are talking £50 to £80 quid per crankset (at 2022 prices) and you need two. Then 3 x chainrings and bolts at, say, £15 each + another £5, so that's you up to £160 to £200.

You can buy crank shorteners but, again, they can be anything from £40 to £160 new. The advantage being they might have 3 or 4 holes, the disadvantage being they spread the kids feet apart and the cheap ones tend only to fit cheap narrow steel cranks.

Highpath Engineering offer a crank shortening service where they take an adult crank and drill it down to a kids size. That's £60 for a pair at present. In theory, if you've got a pillar drill at home, you could DIY it or recycle adult ones you already have. One possible advantage there being that Highpath will do tandem threading, so you could do a crossover pattern. That would allow for 2 or 3 chainrings on the RHS. Or just look neat if done with one chain either side. Sheldon Brown explains, here. You could have the big kid at the front with a dual or triple ring crankset and make the tricycle a 12 or 18 speed (I'm thinking more of for climbing hills than speed trialling here!). Or if your 'pilot' sits at the back, have the gears set up there.

Standard set up:

singlsid.gif (4.24 KiB) Viewed 551 times

Possible crossover set up using tandem cranksets:

crosrear.gif (1.09 KiB) Viewed 711 times

Again, I've found complete tandem cranksets rare and expensive. One of those things that if ever you find a bargain or, or parts thereof, buy and stockpile them just in case. New they are typically, circa £90 for the crossover, or from £180 for a set now, so you can get your money back doing so. Spa Cycles often have specials in this department. Seen some up to crazy prices like £400+.

As a cheap workaround, with compromises, I found a Trek "Dialled" alloy triple chainwheel with 42/34/24T that has 152mm and 127mm crank length hole for about £25. The cranks are really nice. The chainrings are steel junk &, sadly, designed for shifting but not rebuilding. However, at that price, I can afford to gamble. The idea being, I cut off the 24T, use the middle 34T as the primary chain drive, & the 42T as the final chain drive. They also do matching single ring chainsets (for 20" and 24" sized kids bikes for £15). I just matched it with a second 140mm alloy crank off Ebay, which came complete with cartridge bottom bracket for another £25. So, £50/60 quid all in.

One pedal hole is advertised at "8 and under", the other hole as "8 and over", so if the rings work out OK, and the chain lines up, it should do the kids through the age range of the trike. Accepting that even 127mm is really too long for 4, 5, 6 year old. I read about folks using 90mm cranks for 4 year olds. Possibly there's enough meat in these cranks to drill them again?

If anyone has experience on crank sizes & gearing for kids, then please chip in.

[home]

You can certainly have my specs.

If you have a drawing, then post it here, & let's make this a U-Plus 2 master topic.

I was thinking how to include a bearing or bushing in rather than have steel on steel.

[rjb]

A workaround solution for having a chainset on the left side is to use a normal right side set and thread lock the pedals in situ to prevent precession causing them to loosen.
Won't work for clipless pedals unless you strip the pedals from the axles, swap the axles and rebuild them, using more threadlock. It's doable but a lot of faff.
Wish I had seen those cranks a month ago. I fitted crank shorteners to my grandsons bike, cut from a used worn chainset bolted through the existing pedal hole and strapped on with a jubilee clip. Not very elegant and spreads the pedals further apart but he's growing so quickly I think I can remove them in a year's time.

[home]

A workaround solution for having a chainset on the left side is to use a normal right side set and thread lock the pedals in situ to prevent precession causing them to loosen.

Which begs the question, why stop at thread locker? How about clean the threads and then use superglue or JB Weld? Necessity being the mother of ...

Yep, it seems like Trek/Frog range is the best source of cheap, halfway decent, short cranks for their 24", 20", 16" kids' bikes. There was a matching single ring crankset to the one above. May be obsolete now but I've found that there are still plenty of triple rings going right down to £15-ish, also shorter crank holes again. They are generally sold by their kids' bike measure standard, rather by actually length, hence not coming up in general searches.

It's a shame because the cranks are really nice and strong, they are not dished at the rear & so fine to drill out again, it's just that the rings are cheap, pressed steel. Otherwise, they would have been good material for kids tandem conversions.

It's a bug bear of mine that all the, say, Dawes "kidback" tandems, come with 170mm cranks as standard, which is too long even for the little old adult ladies who invariably also ride on such bikes. It's plain wrong, adds an extra £150+ to get right, & just doesn't look right at the end unless you swop the front too.

What's the difference in wholesale costs between a steel and alloy crankset and an all alloy with detachable rings.

[home]

Interesting detail to watch for.

I noticed that the drive axle is only threaded part of the way, the rest remains smoothly machines. I wasn't paying attention when I took it off, and took it to bits, but I'm presuming that this is on the inside of the wheel and acts to keep the wheel aligned and wobble free. It's a tight fit. There's also one tight, narrow washer the width of the inner bearing tube on that end of the axle, so don't drop or loose it.

[home]

Removing the drive axle and freewheel holder turned out to be mercifully easy.

2 x 16mm nuts on the end. A 32mm spanner holding the holder (do we have a better name for it, boss?). The alloy bit that the freewheel attaches to. Normal clockwise thread. No effort required.

In this case, the axle came out with the outer bearing and revealled a mild steel spacer between the two. The bearings are 6002-2RS, which is a double sealed ball bearing of 15mm x 32mm x 9mm dimensions. Really common place.

[Jdsk]

Thanks.

I'll need to know that someday.

Jonathan

[tatanab]

holding the holder (do we have a better name for it, boss?).

Drive boss is the usual term amongst club tricyclists.

[home]

Drive boss is the usual term amongst club tricyclists.

Much appreciated. Do we get to join the club now?

I noticed mine was a little corroded for having two dissimilar metals together, i.e. steel and aluminium. There was some white aluminium oxide in the hole. So, what, something like Copaslip between them to stop the galvanic corrosion, or is grease good enough?

[tatanab]

Do we get to join the club now?

Tricycle Association membership is open to those with an interest in trikes, you don't have to have one. It is also cheap by cycling club standards https://tricycleassociation.org.uk/membership/

So, what, something like Copaslip between them to stop the galvanic corrosion, or is grease good enough?

I would always use a smear of grease. Same in the bearing housings.

[home]

Tricycle Association membership is open to those with an interest in trikes, you don't have to have one. It is also cheap by cycling club standards https://tricycleassociation.org.uk/membership/

I've got a couple of adult tricycles too. Not a fancy racing style yet, but a rare Raleigh Twenty shopper conversion some small shop made.

What's the current line of thought on dishing wheels on tricycles? I know received information says dishes weaken wheels but two small kids on a tagalong trike, with 36 spoke, 20" wheels, aren't going to be stressing them much.

I'm thinking that by dishing them outwards I can gain about 2cm extra width, which will add to stability. (It also helps as I haven't got enough spokes all the right length!).

I can only find one forum post re tricycle wheels and dishes.

Thanks.

[tatanab]

What's the current line of thought on dishing wheels on tricycles? I know received information says dishes weaken wheels but two small kids on a tagalong trike, with 36 spoke, 20" wheels, aren't going to be stressing them much.

Back in the 80s there was much discussion and I know a very few people tried it. The only one I knew personally said it wasn't worthwhile, but we are not talking about offsetting the rim by the inch you have mentioned - in our cases that would make the outboard spokes just about vertical. Also, of course we subject our wheels to much more stress than you are likely to. Given that some of our riders use modern wheels with low spoke counts, you might think that dishing cannot be worse than that - but you have to consider that modern rims are very strong versus those of several decades ago and I doubt you want to change your rims. I don't believe we have anybody these days riding dished rear wheels.

Advantages of a wider track are greater stability in steering through a corner with adverse camber and also greater stability when cornering at speed. For example - a shallow down hill right hand bend I go around regularly has a slight but noticeable adverse camber. On my 1956 Higgins with a conventional 27 1/2" (700mm) axle which gives a track width of something like 24" (trikes are measured "over hubs" i.e. will it go through the door) this bend is enough for me to feel the need to straighten it a bit and move up from camber. On my 2003 Longstaff, again 700mm wide but with a different hub design so the track width is 25" I don't notice the camber as much. On my 2012 Trykit with a 750mm axle and a track width of 27" I don't notice it at all. Note that this is cornering on an adverse camber, none of the machines are bothered about a camber on a straight road. Something else to consider is that the centre of gravity is somewhere above the saddle, dominated by the bladder of lard in the saddle. In your case the CofG will be much lower due to the smaller riders and so (I think) not as sensitive - also your speed is likely to be lower I expect.

Summary - I would not bother, but if you have bare rims and spokes kicking about to do it, then maybe give it a try. If you decide to change the rims, I expect that the existing are 451 and if you change them to 406 (the BMX size for availability of tyres) this will lower the bottom bracket enough that you might seriously need to consider shorter cranks. I did this on a small wheeler that I have and very quickly rebuilt them as 451.

[home]

Back in the 80s there was much discussion and I know a very few people tried it ... Advantages of a wider track are greater stability in steering through a corner with adverse camber and also greater stability when cornering at speed. ... if you have bare rims and spokes kicking about to do it.

Nice trike. Quite close to what I plan to do with the TGA Tri-Shopper I mentioned, but yours is clearly more elegant. The Tri-Shopper is just a Raleigh 20 with a tricycle rear end welded onto it. Think it was a v. early electrical bike. I'm a big fan of the ETRTO 451 size, although I did do one Raleigh 20 with 457 wheel just to resolve the crank length issue you mention. Even less tyre choice with them!

I threw together a couple of wheels, and I might revise the extra width to one inch-ish, or about 10mm+ on either side.

The hubs are 60mm wide and alloy. They polish up well enough without becoming OCD. I've ditched the original rusted chrome rims (80s?) for some reasonable quality BMX rims that are 35mm wide (external). The U-Plus 2 did actually come with 406 rims as standard. I think the bottom brackets are, if anything, a bit high already. Although, yes, I've also shorted the 150mm cranks too (stock photo off web below).

Once it's back together, I'll measure up the rest, unless someone else with a stock one wants to chip in. It's hard to take a helpful photos with phone cam, but ... (there are no rim brakes on this one). First build, so spokes are still loose.

[cycle tramp]

H'mmm.... looking at the last photo, may I suggest that the bicycle doing the towing is fitted with a full rear mudguard and mudflap, otherwise the pilot of the tandem trailer is likely experience an awful lot of rain water and muck kicked up from the rear tyre (and probably put them of cycling forever), or even road dust and grit...
You may want to even consider something like a down tube mounted mud catcher as secondary defence mounted to the tandem trailer.