Evolution of Skill....

[Lenk42602]

Looks like my pics all crapped the bed...

So here is the second set of drop outs I made up - first set I cut the dropouts too wide , too much slop. That sucked.

Here's the basic form of the dropouts - need to clean up the inside a bit..

hey whip,

think I am going with a varition on that idea - the steel is 9.5 mm wide, so I would have a rough go running a hole vertically through the drop out... going to weld a steel bushing vertically where the file is pointing, and a nut on the lower side. I can run a bolt through and be done with it...

On the wheel:

mocked up near the monster swingarm. going to notch out the arms, then weld in the drop outs...

Plan on tacking the swing arm assembly together by the end of the week. Now I am gonna go back and repopulate my thread with pics....

[Factory Phil]

Len,
Great looking build! Can't wait to see more & how you fit in the batteries.
That front tire also looked great, what size rim was that? Also the tire, what size & make was that?

[Whiplash]

Yeah great idea on the dropouts, not only will the bolt allow you to pinch the axle, it will also keep it from spreading under load... keep up the work!

[John in CR]

Lenk,

Great work. WRT the clamping dropouts it seem appropriate to me add a thin slot in the steel to permit a good clamping action. My concern is that without one the clamping bolt deforms the metal slightly to make the axle impossible to remove without filing to enlarge the slot. I've had a hell of a time getting a motor out of a custom snug fit dropout before, and that was with no clamping. Another benefit is that the axle slot can be to big and the bolt snug it right down.

Here are 2 sets of mine, with hacksaw results, so your bandsaw was a great purchase. I did double up my blades though to make the cut a little wider.

Clamping dropouts.JPG (30.43 KiB) Viewed 670 times

[Lenk42602]

@Whip - build got delayed a bit. I landed a part time gig working in A MACHINE SHOP with an old timer. It has been great so far.. Time to play has just been minimized a bit though....

@Phil - Tires are BMX, 20" X 2.4", these: model IA-2021 - http://www.innovatires.com/menu.php?xCPId=B06
......for now.... pulled them off a kids gt stomper 20" bike at the shop I work in....

The rim is a 16" moped rim, DOT approved. Heavy duty. This gives me the option to run bmx tires or 16" moped/motorcycle tires....

I wont be getting back to the frame until after this swing arm is mostly complete. the sequence planned is swingarm, lower main frame (where swingarm pivot point is) main frame w/out head tube area, then attach head tube area, then shock mounts on swing arm (lower) and main frame (upper). then seat tube.

Good lord this takes for ever. I hope it comes out close to what I am envisoning....

[Lenk42602]

Great .... so your bandsaw was a great purchase.

Clamping dropouts.JPG

It would have been impossible to get this far without. Seems jigging material is the biggest challenge to getting the machine to cut well. Takes all of the sweating out of the equation....

DIdn't consider the slotting idea. makes sense. The drop outs are snug right now, so I will add the clamps prior to the welding phase of the swing arm and determine if I need to slot them..

Len

[Lenk42602]

Back on the horse.....

Got slowed with this build due to a terrible sickness over the last few weeks and work.... I think (hope) the last green caterpillar decided to crawl out of my right nostril this am. No bacon frying yet, but while sick I was able to fit the critical head tube junctures to tight tolerances, as well as notch the rear swingarms to accept the dropouts.

head tube, (top tube frame rails)

drive side swing arm pieces + dropout clamped/magnet jigged together..

We have been in the mid/upper 30's for the last few weeks. This simply should not be at this time of the year in pittsburgh.... Hopefully we will be in bacon frying weather soon.... You may notice the amount of tire clearance, I want to be able to run this size wheel as well as 24" mountain bike rim on the back in the future, so I gave myself some room......

Len

[johnrobholmes]

Just ran across this thread, great build you have going! You do all the dropout work with that band saw? Maybe drill a pilot hole for the rear of the dropout slot? I had been trying to make the same sort with my jig saw, and it just wasn't cutting the thick steel well enough to keep going with the work. In the mean time I think I figured out a way to make a clamping dropout without needing to use super thick stock, but I gotta make it before saying it actually works.

I'm so jealous of those wheels I built for you. Sooooooo jealous. Thanks for the kind words!

[Lenk42602]

yeah john, that little 4X6 bandsaw has been the key to all of the cutting everything parralel, square, etc..

I basically just took the two dropout blanks, clamped them together, put them in the carriage, and then let the saw drop. Then I flipped over the clamped dropout blanks and cut the other side. Had to hacksaw about 3/16" on each side to level them out, and then I used a drill press to round the back of the dropouts. Then the hand filing. More hand filing. Cut the dropouts to 9.28mm, then I hand filed the dropouts the axle sits in so that it is SNUG.

Keep me posted in your dropout clamp idea. I am a little nervous about running a hole vertically through dropouts and then tapping it for a cap bolt. I just don't think I can do so very straight with a bolt large enough to have any clamping force given the width of dropouts. Thats why I am leaning toward the more crude pinch bolt at the back of the dropout idea...


Len

[johnrobholmes]

Mine is more of a sliding dropout/ lollypop/ pinching idea where the pinching body keys into the dropout and also handles chain tension.

[gtadmin]

Mine is more of a sliding dropout/ lollypop/ pinching idea where the pinching body keys into the dropout and also handles chain tension.

Hi John, do you have those thoughts as a sketch? Sounds interesting. (Len sorry for the hijack)

Cheers,
GT

[johnrobholmes]

Not yet, just in my head still. I will see if I can sketch or CAD them out soon and keep milling machines out of the construction needs.

[gtadmin]

Not yet, just in my head still. I will see if I can sketch or CAD them out soon and keep milling machines out of the construction needs.

No worries. I've found that it helps to solidify an idea.

[Lenk42602]

Made some progress today - swing arm is tac -welded together. stopped at the pivot & BB bracket area. Still have some final decisions to come to before striking an arc.

So I measured my clearance in the swingarm regarding wheel diameter. I can run anything from a 20" - 26" tire diameter. I am going to have to start thinking about different mounting brackets for the rear suspension depending on what wheel diameter I am running. I will need some kind of "riser/spacer" when running the shorty wheels. I also have to consider BB height and decide if I want to just run short armed bmx cranks (140-150mm) when I am running these 20" wheels, and then run longer, conventional length crankarms when (if) I switch back to a taller wheel. This is why I stopped where i did on the swing arm...

Everything ended up pretty square/straight....

So if anyone with a sharp eye can see, I decided to re-cut the sections of the swing arm that attaches to the dropouts; on my first attempt, I just notched the inner side of these sections to accept the dropouts. Today I decided to do them over again, and slot these sections down the middle to allow for more welded surface area/ strength...

I didn't bother changing my wire today to a smaller guage - thus the glob tac welds.... Plus she's mad at me for neglecting her all last month..

On another note, I was having a hard time sourcing a tube with an ID that could fit ANY conventional bicycle seat post size. Fortunately I found 1 - 3/8" OD X 1.245 ID tubing (.065 wall)

- turns out this works very well with a 31.6 mm seat post.

Bonus....just happen to have 2 different posts of that size here at the house. I was going to weld on a pinch bolt/nut to secure to post, but the fit is so perfect, I think I can get away with slotting the backside of the post and using a conventional 34.9 seatpost clamp/collar...

Its such a motivator when your project starts moving from 2 dimensions to 3 dimensions!

Len

[gwhy!]

Hi Len,
Looking good ,
I just thought I would give you the heads up about your bicycle shock so you dont have to go through the same sort of stuff I am at the mo, The shock spring will need to be the stiffest you can get. I have a similar shock position and stroke and my shock came with a 550lb spring fitted as standard but its way..way to soft . I have had a play with a cheapo shock that is fitted with a 1200lb spring and this is much better, but the problem I have found is trying to find a 1000lb+ spring to fit my shock body, the stiffest one I can find for my shock (at the mo ) is a 800lb and I am waiting delivery and hopeing that this will be stiff enough.
Cheers,

[Lenk42602]

Gwhy,

I have a 600 # manitou swinger shock, pictured on the left

and 1000# motocross rear shock from a company called Fast Ace, pictured on the right:

I am torn - I spoke with Hal about his rear shock set up on the Albino V2 project many moons ago, and he described the exact same issue you are dealing with. For that very reason, I went with an actual motocross shock initially. The only probem is that the shock weighs close to 4 pounds rather than the mtb-specific Manitou @ roughly 1.25 pounds.

He was taking about sourcing a custom 1000# spring for his mtb shock. I hope YOU figure it out before I get to that point so I can use the solution

Len

[gwhy!]

Hi Len,
I have now fitted a 800lb spring ( was 550lb) on my 200mm i2i shock and I makes it very nearly acceptable for my needs ( but not quite ) but I think it will still be far to weak for any form of road riding. So now Im on plan C the stroke on my shock is around 3cm'ish and im using about 2cm'ish so I think im going to look for a 165mm i2i decent shock and move the shock mounting points to keep the same ride height and Im hopeing that the 2cm'ish travel will be enough without bottoming out. It is very easy to get springs for this length of shock upto 1200lb buy buying a very cheap tacky shock just for the spring. I am running out of plans now but I do have one more plan D which is to have 2 shocks a longer stroke ( with the 800lb spring ) in parallel with a shorter one with a stiffer spring but to have some form of free travel on the shorter one. This may be perfect for my use as it will make the suspension very tunable for what I want and it will still be lighter than a proper motorcycle mono shock.

Edit: I have been looking for a oil over coil short ( 165mm ) shock and now im not totally sure if the the cheapo shock springs will fit over the shock body.. I need to do a bit of reasearch before I decide

Have anyone reading this got a coil over oil 165mm i2i shock that can give me the shock body dia from, this would be a great help.

[Lenk42602]

Sounds do-able with a shorter-travel mtb shock+1200 lb spring.

However, I want a bit more than 2cm of usable travel.

Keep me posted -

Len

[gwhy!]

My longer shock is 4cm'ish travel and using just under 3cm of the stroke ( I was getting my numbers mixed up and I lost 1cm somewhere ) and 165mm i2i would be about 3cm travel. Its never a good idea to use the full stroke of a shock as it do put even more strain on the internals but it might be the only way forward for me at the moment. The total wheel travel is more than enough using the just under 3cm of shock travel. I will let you know how I get on.

[Lenk42602]

Lunch break -

Sides of the main frame tac welded in place. I've clamped the cross braces in place. Head tube & last sections of top/down tube frame pieces are going to be the real challenge - particularly getting the head tube right ... That area I will be jigging to get right....

more to come

Len

[Lenk42602]

Cross braces for the main frame tac welded in. Now onto the head tube sections.

Top frame sections connecting the head tube held in place with a magnet.

Want to get the head tube angle pretty to close to where I designed it, so this part is going to take some time. That hunk of steel weighs a good bit already. Going to have to come up with composite material of some sort for the panel insets to manage the total weight a little....


Len

[johnrobholmes]

The headtube is my least favorite part of the build. The rest of it can be a bit off, but if the headtube is off the entire bike is garbage.

[Lenk42602]

couldn't stand it.

mocked up again with the bits and pieces I have so far...

I have compression straps on the front fork to account for sag. At this height, I would be fine with running the moto bars. I have some clip ons that fit the upper stanchions on the fork.

I guess we'll see what pans out....

Len

[johnrobholmes]

What front end is that? From a mtb?

[HAL9000v2.0]

From where I am standing it looks like old SR Suntour Sigma fork.