Any Technic Cyclists?

[quilkin]

Hi all

I've recently come back to Technic after a 20-year gap and am finding all the new studless parts & techniques far more interesting than the studded ones. OK, I'm aware that my opening statement may cause some controversy. Anyway, I've recently got 2 new sets (8292 and 8265) as well as several small Bricklink orders.

I'm building a one-third scale model of a racing bike, and am now satisfied with wheels, frame, brake, chainwheel, etc (even a water bottle). But I can't figure out any parts to use for the wheel drop-outs, and also how to make the wheels spin on a fixed axle. The drop-outs ideally needs to be a part with a slot just wide enough for an axle. The current arrangement means that the whole axle needs withdrawing from the frame in order to remove the wheel. (OK I know this bike on't ever get a puncture) I could get the wheel to spin by drilling out the center of the pulleys I have used for the hubs, but modifying Lego parts isn't allowed!

Maybe there's the ideal parts hiding somewhere amongst all the Pirates or Bionicles sets that I know nothing about. Any ideas? When the whole bike is ready I'll post details here, if anyone's interested....

[DLuders]

I'm familiar with a real bicycle's "dropout" (where the wheels can be removed by simply loosening a nut that has a lever on its side). I just looked at all of the Lego Bionicle pieces on Bricklink.com's Catalog pages (http://www.bricklink.com/catalogList.asp?pg=1&catType=P&catID=273 ), and didn't see any STOCK parts that could work without modification. However, even if Lego actually MADE a Technic Liftarm with a notch on the end-most hole, could a Lego wheel actually STAY ON IT by "pinching" the liftarm with Technic Bushes? There are old Technic threaded axles (http://www.bricklink.com/catalogList.asp?q=threaded ) and corresponding nuts (http://www.bricklink.com/catalogItem.asp?P=4698 ) that one could use IF you're willing to saw-off the end of a standard Technic Liftarm to make the forklike "dropout". Alternatively, you could cut off the end of the Bionicle part #47334 (http://www.bricklink.com/catalogItem.asp?P=47334 ) to expose a "dropout" fork. Go through the various Bionicle pieces at http://www.bricklink.com/catalogList.asp?p...&catID=273; maybe there is a part that you like better.

Lego pieces can make ALMOST anything, but not everything....

Edited January 12, 2010 by dluders

[Sumendar]

Would a couple of these next to each other on an axle and pinching the wheel axle between them work? Probably not the most life-like or prettiest solution out there, but at least they would allow quick change of wheel.

[brickzone]

Well, it may be an unsatisfactory approach, but rather than try to arrange the exact mechanism used in real life, how about instead just arranging a technic mechanism to acheive the same result - i.e. simple drop out of the wheel?

So for example, could you use a shorter axle that only reaches halfway into the bushing either side of the wheel hub, and use two short axles (2L red for example, or some connector with short axle sticking out) as "pegs" that you just pull either side of the wheel to release it?

Presumably there are other approaches to the concept of just two little stubs you pull either side of the wheel fork to release the wheel? Maybe not as satisfying as duplicating the real life mechanism, but it might be a challenge to acheive an alternate approach to wheel drop-out in a slick non-kludgelike manner?

[allanp]

For the hub you could try these:

http://www.peeron.com/inv/parts/2695

I know they are wider but then the hub is the widest part of the wheel. I think it would be fairly easy and more interesting to emulate the way in which the spokes are placed wider at the hub, either side of the hub and then come into the centre line of the wheel as it reaches the edge of the wheel if your spokes are long enough.

As for the drop-outs, I would think that your forks would have to be about 3 beams thick in order to look in scale. This being the case you could have your three beams stacked up using the blue, 3-long friction pins, so the holes of the beams are facing each other, leaving the middle beam 2 holes shorter than the outer two, giving you your drop out. Then you can put bushings on the axles to make them fit better without moving around so much and either use those threaded axles mentioned earlier, using these http://www.peeron.com/inv/parts/4185 as washers or a removeable pin through the bottom of the fork.

I realise i'm probably talking on a bigger scale that what you intended (probably 1/2 or something) but I hope this helps. Would love to see it when it's finished.

[Parax]

Perhaps you should take a tiny bit of the frame with you when you dropout the axle?

Edited January 12, 2010 by Parax

[quilkin]

Many thanks for all the suggestions!

Yes, my forks were too thin, after some experimenting I found that a double liftarm 32271 held together with some 4x2 studded plates makes the perfect slot for an axle. And I didn't realise that the 2695 wheels were free-spinning, that's good. I know about the threaded axle but the little nuts are too fiddly, I think I can use some discs 2958 on normal axles to clamp them in place.

So, next stage is to somehow get the rear sprocket driving the 2695 hub without driving the axle. (It's a single-speed 'fixie' by the way, maybe designing a derailliuer and freewheel in Technic is going a bit far for this stage.)

[allanp]

Many thanks for all the suggestions!

Yes, my forks were too thin, after some experimenting I found that a double liftarm 32271 held together with some 4x2 studded plates makes the perfect slot for an axle. And I didn't realise that the 2695 wheels were free-spinning, that's good. I know about the threaded axle but the little nuts are too fiddly, I think I can use some discs 2958 on normal axles to clamp them in place.

So, next stage is to somehow get the rear sprocket driving the 2695 hub without driving the axle. (It's a single-speed 'fixie' by the way, maybe designing a derailliuer and freewheel in Technic is going a bit far for this stage.)

That's tricky. The large turntable and diffs do not accept chain drive very well at all and this gear http://www.peeron.com/inv/parts/6542 is too small. I will give this more thought and if I come up with anything better i'll let you know. But for now, one way you could drive a hub without driving the inner axle could be to make a large gear by having 6 of these gears http://www.peeron.com/inv/parts/4019 in a circle. You could do this (I say could, havn't tried it myself!) by placing six of these peices http://www.peeron.com/inv/parts/43093 in the six outer hole of the hub. Then place either a pair of these http://www.peeron.com/inv/parts/41677 or one of these http://www.peeron.com/inv/parts/60483 on each pin. Then, with some messing, you should be able to mount your 6 of these gears http://www.peeron.com/inv/parts/4019 onto the ends of the 1x2 liftarms. They should form a rigid circle if done right but I wonder if the spacing between teeth would be a problem for the chain, and the look of a hexagonal gear might be a bit crappy if the chain doesn't disguise it well. If I think of anything better i'll let ya know.

[quilkin]

Thanks again, allanp. Your ideas have put me on the right track; the set of 6 x 4019 gears is too big (and the liftarms make it too wide as well) but the same idea works fine with 8-tooth gears, and I can even fit the spoke retainers underneath!

Some nice mathematical patterns emerging here...

[allanp]

Thanks again, allanp. Your ideas have put me on the right track; the set of 6 x 4019 gears is too big (and the liftarms make it too wide as well) but the same idea works fine with 8-tooth gears, and I can even fit the spoke retainers underneath!

Some nice mathematical patterns emerging here...

Guess I keep thinking in the wrong scale

I'm glad to see all the gears mesh nicely. I notice the gears are only on the pin by half a stud. I guess you could try using these http://www.peeron.com/inv/parts/6587 instead of these http://www.peeron.com/inv/parts/43093 (with the stop inside the hub) and joinig two opposing ones using one of these http://www.peeron.com/inv/parts/6632 inside the hub, with the fixed axle passing through the center hole there by stopping the gears rotating, making the whole thing a bit more rigid and providing you with a whole stud length on which to mount the gears whilst still allowing the hub to spin freely on the axle.

[quilkin]

Would love to see it when it's finished.

It's pretty well finished (for now at least) - you can see it here - including working brake, dropout wheels, water bottle, and pump (!). I started with the frame, (I have mostly yellow beams) then found the cheapest 1x2 thin liftarms (for the rims/tyres) on Bricklink were red or gray. Yellow 2x1 liftarms were not ever made! Maybe I'll do a red frame one day to match.

About the wheels, is it off-limits to strain Lego parts in this way? Real bike wheels are under a lot of stress, they have to be, so I maybe it's OK.

Thanks again for help from contributors.

[JunkstyleGio]

nice pics!

But:

no rear brakes?

[allanp]

It's pretty well finished (for now at least) - you can see it here - including working brake, dropout wheels, water bottle, and pump (!). I started with the frame, (I have mostly yellow beams) then found the cheapest 1x2 thin liftarms (for the rims/tyres) on Bricklink were red or gray. Yellow 2x1 liftarms were not ever made! Maybe I'll do a red frame one day to match.

That looks great. Lots of very nice and realistic details there. Well done.

About the wheels, is it off-limits to strain Lego parts in this way? Real bike wheels are under a lot of stress, they have to be, so I maybe it's OK.

I guess you answered your own question! Tho it's probably not something i'de like to do, it seems to have worked very well. It would be difficult to find a better solution, and near impossible to do without spending lots of money on bricklink.

Thanks again for help from contributors.

You're welcome

[sverre]

Great MOC you built! I´m a bike maniac and love all kind of bikes, so I find this MOC especially interesting. The brake and wheels are ingenious.

[quilkin]

nice pics!

But:

no rear brakes?

Yes, it's a 'fixie' (fixed-wheel bike); there's no freewheel so you can back-pedal to stop it. Rear brakes aren't required (or even legally required!) on fixed-wheel bikes. Also a rear brake would need some very long flex cables; I tried joining some together but wasn't happy with the results. A freewheel won't be impossible, maybe that can be a future project, but I think I'll go for 1/2 scale rather than 1/3 scale if I build another.

[Tobbe Arnesson]

I stumbled across your bike before I found this thread, it's very well made!

Perhaps the best rendition of a larger LEGO bike I've seen!

At an AFOL gathering back in 2005 I saw the Hailfire Droid wheels for the first time and started on a LEGO MTB, just a design study with another AFOLs bricks so take it for what it is:

I might have to revisit this some day or another...

Edited February 16, 2010 by Tobbe Arnesson

[quilkin]

I stumbled across your bike before I found this thread, it's very well made!

Perhaps the best rendition of a larger LEGO bike I've seen!

At an AFOL gathering back in 2005 I saw the Hailfire Droid wheels for the first time and started on a LEGO MTB, just a design study with another AFOLs bricks so take it for what it is:

I might have to revisit this some day or another...

I saw those wheels in some photos somewhwere on the web and wondered what they were - thanks for defining them - but they're $25 each at Bricklink! I think mine built from parts were cheaper and could be built to a range of sizes.

I've built more large wheels since then (not bike wheels), I'll post some pictures in a new thread soon.

[Tobbe Arnesson]

they're $25 each at Bricklink!

Yikes!

Guess being a one set only part and a quite unique one at that has it's toll. I should have bought the set when it was in production. :(