T50 - whatcha planning to build.....

[Brad R]

I did a shakeout ride today and learned a couple of things that might help the rest of you.
1) Make sure the boom slider clamp is really, really tight. I had it come loose twice in the first few miles. The first time the crank completely separated from the boom and went all the way to the ground.
I am going to rig a restraining cable until I understand what happened and learn to trust the clamp.
2) You can adjust the seat forward or back about 2 inches. I initially had it all the way forward, which for me and my long legs meant the boom was extended close to its limit. Maybe that is why the clamp came loose.
3) After a few miles the chain loosened and kept falling off. Its a Rohloff hub without a chain tensioner so this should not affect most of you.
Hopefully this is normal break-in and I can tighten the chain and get away without the chain tensioner, but only time and miles will tell...

4) It was fun to ride! I cruzed the waterfront a couple of times until I decided to take it home and fix the above issues.

@Bill K

Thanks for posting about the boom slip. I have been very careful about getting the clamp very tight and making sure the clamp was fully seated.

Did you create the retainer you mentioned?

Up until tonight, I only had one instance of a few cm of slip during a hard climb. I didn't notice until I saw that the boom had moved from my pencil line. (Had marked my spot and my son's spot.)

Tonight I went for a ride with my son. We stopped in a park and we adjusted the boom so he could ride around in the park. After putting it back in position for me and securing the clamp with a lot of force, I had a complete separation event on the ride home. And then, two more severe slip events on the balance of the ride.

I wrote to Cruzbike Support requesting the extra clamp.

My BB retainer was my clipped in feet and I was able to prevent damage or falls. But it was a little nerve racking. I am glad I had switched over to my SPD pedals. I am sure the the pedals and chainring would have been on the ground if I still had the platform pedals.

The good news for me is that I am getting comfortable enough that I was able to handle the event without panic, damage, or injury. It helped that I was going uphill rat less than 10 mph.

My outer boom tube does have the slot to allow it to compress onto the inner boom tube.

I have a green bike with the silver tubes. I don't know if we got something slick on the tubes and spread it to the inside of the outer tube when my boy was riding or if there is some other cause.

Are there suggestions for how to clean or prepare the tubes to improve the friction between them?

Would a small hole with a through bolt be a good idea or would it weaken the tubes?

 

[Bill K]

Did you create the retainer you mentioned?

I rigged an old brake cable as a restraining cable (looped it thru the headlight mounting bracket and around the steering tube riser). I took it off about a week later when I was confident that the boom would not slide out again.
Here is what I did to solve the issue:
- Move the seat all the way to the back (I'm also using the EuroMesh seat, not because of the boom extension, I like the mesh ventilation in the summer). Because of this the slider is inserted over 4 inches into the boom. When it came loose it was very close to the max extension.
- Removed the quick release handle from the boom clamp. You can get it much tighter using a 4mm hex wrench than you ever could with the quick release.

I would not recommend drilling a hole and bolting the slider. You will likely want to adjust the length 1/4 inch in or out, and maybe several times before you settle in on the perfect setting. Try removing the quick release lever and using a hex wrench to tighten the clamp while you are waiting for the additional clamp from CB.

The good news for me is that I am getting comfortable enough that I was able to handle the event without panic, damage, or injury. It helped that I was going uphill rat less than 10 mph.

Definitely good news!

 

[super slim]

The slot should be 32 mm long by 4 mm wide with a drilled 6 mm end for a 13.5 mm wide clamp, as per Quest V1.0. to allow the outer to be deformed slightly to clamp the solid inner tube. see attached photo.

I had to remove the Quick release on my Softrider, and Quest boom clamps as they were Always slipping forward under heavy start up loads.
I then had to apply Moly to the M6 nut, thread and to the added M6 steel washer for the nut, so it did not dig into the soft Aluminium clamp, and reduce the clamping force down to 1/4 of a steel to
steel lubricated bolt set up.

 

[Vicki C.]

@Bill K

Thanks for posting about the boom slip. I have been very careful about getting the clamp very tight and making sure the clamp was fully seated.

Did you create the retainer you mentioned?

Up until tonight, I only had one instance of a few cm of slip during a hard climb. I didn't notice until I saw that the boom had moved from my pencil line. (Had marked my spot and my son's spot.)

Tonight I went for a ride with my son. We stopped in a park and we adjusted the boom so he could ride around in the park. After putting it back in position for me and securing the clamp with a lot of force, I had a complete separation event on the ride home. And then, two more severe slip events on the balance of the ride.

I wrote to Cruzbike Support requesting the extra clamp.

My BB retainer was my clipped in feet and I was able to prevent damage or falls. But it was a little nerve racking. I am glad I had switched over to my SPD pedals. I am sure the the pedals and chainring would have been on the ground if I still had the platform pedals.

The good news for me is that I am getting comfortable enough that I was able to handle the event without panic, damage, or injury. It helped that I was going uphill rat less than 10 mph.

My outer boom tube does have the slot to allow it to compress onto the inner boom tube.

I have a green bike with the silver tubes. I don't know if we got something slick on the tubes and spread it to the inside of the outer tube when my boy was riding or if there is some other cause.

Are there suggestions for how to clean or prepare the tubes to improve the friction between them?

Would a small hole with a through bolt be a good idea or would it weaken the tubes?

Well, I now feel a little better that I am not the only one whose boom went boom. I was riding to the bike shop and wondered why it seemed that my pedal distance was off. I kept moving the boom and reclamping it and it seemed to be as tight as possible and then the pedals moved again. All of a sudden my left pedal was in the ground and the boom was completely apart. I scraped the crank arm and the chain ring guard or whatever that part is called. The road was a little rough. The bike mechanic used an Allen wrench to further tighten the clamp and I have had no further slippage, even when trying to power up a short 12% grade.

Hopefully that won't happen again. Is there an additional precaution I should take?

 

[SlowRoll1950]

Nice green and good job done! I am also setting up with 1x11 front 32t rear 10-42. Did use 114 link chain? I might need to order 2 sets of chains learning from you. This is my first build too other than I have done some upgrade to my Moulton TSR-9 a couple years back. Wish me luck.

Turns out I didn't need extra links. It was a chain gap problem fixed by the B-adjust screw. Once properly set the 116 link chain worked like a champ. It might be a little long for a 42T.

 

[DavidJL]

Just got done doing the Emeljay steering mod to the T50. Also cut 1.125 inches off the strut tubes, drilled and slotted for clamping and found out I also needed to cut the seat brace because the inner diameter of the strut tubes is a bit larger close to the bottom ends. Also had to cut down the steering tube. Pix to come. By the way, I did find it hard to get the riser off the steering tube. I had to clamp a longer stem on to get a hold. And the riser went on fairly easily.

 

[DavidJL]

Pix

 

[Brad R]

Just got done doing the Emeljay steering mod to the T50. Also cut 1.125 inches off the strut tubes, drilled and slotted for clamping and found out I also needed to cut the seat brace because the inner diameter of the strut tubes is a bit larger close to the bottom ends. Also had to cut down the steering tube. Pix to come. By the way, I did find it hard to get the riser off the steering tube. I had to clamp a longer stem on to get a hold. And the riser went on fairly easily.

When I took my riser off, I first slid the boom clamp up out of the way. Then I used a large bladed screw driver to spread the slot on the riser a little and used @ratz suggestion of WD40. I also kept handlebar on for adequate leverage.

Let us know how it rides with the modification.

 

[DavidJL]

So far, the steering mod rides fairly nicely similar to what I have already done with the QX100. I picked up some creaking. Not sure where it's coming from yet, but the boom tube fits very closely, close enough that I have to loosen front derailleur and front cable stop. It is best to have it this way to insure boom tube doesn't rattle. The Razor scooter clamps are a nice touch. I did have to go to a machinist to get the boom tube to fit right. The rest I did with drill press and table saw set up to cut aluminum. The trickiest part was cutting the slots without cutting into the holes. I am thinking about using two more Razor scooter clamps with two QR seat skewers to make the seat adjust without tools. From a few spins, the seat angle does not appear to require a neck rest. Not planning on going full 'detta with the seat angle...

 

[trapdoor2]

Pix View attachment 5226 View attachment 5227

Nicely done!

 

[super slim]

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Excellent neat Emeljay conversion, with a lot of handle bar height adjustment!!!

 

[Emeljay]

I picked up some creaking.

I have some rattle/creaking on my X100 that I found out comes from the cassette being loose because there is a space created when I took off the plastic spoke protector after it cracked.

 

[DavidJL]

I should mention that if you use a front derailleur, you have to keep the boom-chainstay angle closed to about 80 degrees. For this reason I had to cut down the fork to make it more like what's on the QX100. I don't recall having a spoke protector on my QX, though it might not be a bad idea, given the drive wheel being up front. I haven't checked the chainring fixing bolts yet. I wonder how many T50 and QX owners will end up doing this mod. It wouldn't surprise me if the QX disappeared from the lineup, but it is still the bike to get if you need to break it down for shipping. Thanks for the interest.

 

[Brad R]

@DavidJL
I have my handlebar forward of the steering mast on the stock build and if my cables were longer, I would explore moving it farther forward. It seems that my elbows would have to be behind my head if I did this mod on the T50 unless I moved the seat back about 6-10 inches.

Are you sitting with your elbows bent at an acute angle?

 

[Rampa]

Back in the Freerider days of yore, the handlebars were attached to the boom via an adjustable stoker stem. You could do something similar on the T50.

 

[DavidJL]

The other part of the steering mod is decreasing the seat angle. By moving the mounting holes in the seat up three inches and cutting 1 1/8 inches off the strut and seat brace, I have a seat angle just barely not needing a neck rest. With the steering mod, the knees are not underneath the bars. I do have shorter than average arms, so your mileage might vary. The bars have to be not only lower but further back to clear the thighs. It is a very tight design with just enough room, so experimentation is required.

 

[DavidJL]

I am guessing that not much force could be put on the bars without serious flexing, but the old Freerider sure looks cool.

 

[Rampa]

Pix View attachment 5226 View attachment 5227

That front-end looks really clean and nice with those scooter clamps! Very nice mod, indeed.

 

[Rampa]

I am guessing that not much force could be put on the bars without serious flexing, but the old Freerider sure looks cool.

I would use flat bars with the stem attached just forward of the pivot-clamp on the upper tube.

 

[super slim]

The other part of the steering mod is decreasing the seat angle. By moving the mounting holes in the seat up three inches and cutting 1 1/8 inches off the strut and seat brace, I have a seat angle just barely not needing a neck rest. With the steering mod, the knees are not underneath the bars. I do have shorter than average arms, so your mileage might vary. The bars have to be not only lower but further back to clear the thighs. It is a very tight design with just enough room, so experimentation is required.

Could you use MTB drop bars like on the Silvio?