Fork issues, motor recommendations, and other newbie questions/issues

[Kemosabe70]

I bought a rear 12t from Em3ev last night and a new rigid chomoly fork the other day to fit to this bike

Sorry memory is very poor.

I'll go hunting, ignore these if already there

Link to the fork?

How about 135mm dropouts? I want to go fatt

https://www.modernbike.com/soma-lugged-cx-disc-fork-700c-1-1-8---black#productreviewsheading


Sent from my iPhone using Tapatalk

 

[AngryBob]

Speed and acceleration are the enemy of range. Wind resistance over 20mph becomes a major factor.

Large, heavy, DD motor in a front fork is just a very bad idea. Front fork snaps off at speed serious injury is likely.

700C wheel is like putting motor into a high gear, all the time. Gain speed, lose torque. Small wheel has opposite effect. If only there was a small, lightweight motor with 2-speed, internal gearing change. There was, I looked at it hard, but it was poorly engineered and just was not reliable. Some folks find a 40-50% failure rate acceptable, and argued hard for it, but they were paid shills and other, reputable users told the truth. That POS is no longer sold, even by the shadiest of vendors.

You must decide if you want a light motorcycle or an improved bike. My decision prioritized reliability, range, no drag even with dead battery. Speed and performance were secondary.

To describe my build - Walmart GMC Denali, 700c, STEEL forks, inexpensive. Many thousands of road miles before motor, works fine. Old-guy seat and handlebars upside down. Oversize tires also added. Stock with 48-13 max gearing. I need to peddle at least some, long story, but mandatory. Faster speeds you need some extreme gearing to be able to pedal effectively, especially with a slow cadence.

Motor - MXUS XF07 350W, geared, front hub. on 36V, 18.5mph max, all-day speed. Climbing ability minimal, as is acceleration, but those are what I use the pedals for. 36V, 15AH battery gives range of 30 miles with minimal pedaling - Startup and acceleration, when maximum range-sucking power is needed. Motor has outlasted one bike and one battery, on second of each. Weight around 6 pounds. Effect on dropouts undetectable on examination.

This november will be 6 years of daily use as only transport. Approx 15,000 miles, not problem one. No maintenance whatsoever, never cracked the case, frequent torrential downpours, no water issues, other than a dead throttle twice until I blew the water out.

I did not pick this motor at random. I have read every problem report posted here and several other sites for the last 8 or more years. Go ahead, look, see if you find one on this motor, or similar models. Part of that is that it just ain't a hot-rod motor. I don't need to get there fast, I just need to get there.

The Mac is a good unit, and Paul a reputable dealer, but you will really need to go easy on the throttle to get the range you want, and most people just will not do that. Zoom, Zoom, if it is there, you will use it. I had to have the range and did not have to have the speed, so, easy decision.

 

[john61ct]

https://www.modernbike.com/soma-lugged-cx-disc-fork-700c-1-1-8---black#productreviewsheading

Thanks much! Is there a way to tell how fat a tire it will take?

Would it be a problem going down to a smaller wheel size to get a fatter tire to fit the fork?

 

[John in CR]

5 pages and no one is letting you know that little battery isn't going to get you 30 miles of range with no pedaling.

 

[amberwolf]

I mean is it really that hard to stretch this thing a little more than half an inch? :lol:

Hard? No. You can use an old axle and a couple of nuts with washers, on the inboard side of the dropouts, and some hardware on the end of the dropouts to keep teh axle from pushing out of them as you stretch the frame.

But...it might be hard on the frame, especiallly if it's aluminum. It probably won't break, but it adds stress to the joint at the BB where it meets the chainstays, and the joint at the brake/fender arch where it meets the seatstays (or the seatpost if there's no interconnecting crossbar before that). Whether that ever causes problems, you will find out eventually,

If that doesnt' cause any problems, one other thing you want to do is adjust the dropouts to be parallel (they won't be after you widen the frame), so the axle shoulder and axle hardware sits flat against the surface without gouging into it.

 

[MadRhino]

The easy options for a narrow single speed frame is the small hub kit for the Brompton, or a BBS kit.

It is not impossible to mod the rear triangle to make 135mm dropout width, but difficult to do it straight and precise. I would prefer to weld bolt-on dropout mounts, and be free to fit any width, length, and positioning that I need with custom dropout plates.

1117E582-DF5E-4EDD-A792-3758E8AFEAFC.jpeg

That’s a great idea, there’s a steel fabricator down the block by me that has pictures of bike frames on his google page. I left him a voicemail asking if he could weld on a custom drop out plate.

I’d assume rim brakes wouldn’t be an option if I were to move the wheel that far back, so I guess I‘d have to get a disc brake mount welded on as well?

If you look at the left dropout plate, you will see that a standard IS brake mount had been integrated in the cut pattern. The standard brake mount drilling pattern can be downloaded, to make sure your dropout plate is a precise fit with any caliper bracket.

 

[Kemosabe70]

I’m strongly considering getting a Surly Ogre frame and building that thing up with a single speed.

I’m going to see if I can salvage my handlebars and seat/seat post on the street king and use it on the new frame...will be getting my digital caliper delivered today...


Any thoughts on this?

 

[Balmorhea]

I’m strongly considering getting a Surly Ogre frame and building that thing up with a single speed.

I’m going to see if I can salvage my handlebars and seat/seat post on the street king and use it on the new frame...will be getting my digital caliper delivered today...

Any thoughts on this?

Ogre is a good frame with room for 29 x 2.5” tires. What is it about your bars and seatpost do you want to keep?

The wheels from Street King aren’t wide enough to support the wide tires you can fit in the Surly frame; maybe 700x40 at most. And the Street King’s rear axle spacing is a lot narrower than Ogre’s. Those sealed bearing hubs have a proprietary shouldered axle, which you can get, but not in a long enough length to fit the Ogre.

 

[Kemosabe70]

I’m strongly considering getting a Surly Ogre frame and building that thing up with a single speed.

I’m going to see if I can salvage my handlebars and seat/seat post on the street king and use it on the new frame...will be getting my digital caliper delivered today...

Any thoughts on this?

Ogre is a good frame with room for 29 x 2.5” tires. What is it about your bars and seatpost do you want to keep?

The wheels from Street King aren’t wide enough to support the wide tires you can fit in the Surly frame; maybe 700x40 at most. And the Street King’s rear axle spacing is a lot narrower than Ogre’s. Those sealed bearing hubs have a proprietary shouldered axle, which you can get, but not in a long enough length to fit the Ogre.

I just like the fact that keeping the seat post and handlebars means I don’t have to spend more money :lol: , but it looks like the seat post won’t fit, so I’ll need to replacement and
a new front wheel for sure.

Any recommendations on a brake set up?

Maybe I’ll get a suspension seat post as well

 

[markz]

Any recommendations on a brake set up?

Use cable actuated disc brakes and not oil

 

[Kemosabe70]

I am deciding between the surly ogre and straggler frames. Straggler has a forward-exiting horizontal rear drop out and the ogre has a horizontal slotted with an optional vertical dump-out.

I really like the looks of the straggler, but the ogre seems easier to install a torque arm onto. What do you guys think I should go for?

 

[Kemosabe70]

Bought the Ogre, considering building it up myself or just taking it to a shop. Building it is really daunting, but I feel as thought once I’ve figured it out I probably wouldn’t want to ever do it any other way, and I love that feeling. On the other hand, I’ll be barreling down a busy NYC street at 20mph so maybe I should leave this one to the professionals?

Any recommendations on a good gear ratio for the single speed? Not sure what my average speed would be factoring in all the stop and go but I’d like to be able to put power down at all times on flat terrain.


Really like the white industries rear cog, sounds SO clicky and clean, but maybe it’ll get annoying being that I won’t be pedaling that much.

Also, what should I be looking for in a front wheel in terms of materials? Any good cheap brands out there?

On a side note...my buddy is taking the street king off my hands, purchased an Ebikeling kit and is going to cold set the rear drop outs to fit the 135mm rear hub. Essentially doing what I set out to do in the first place :lol:
He’ll also be purchasing the Soma fork from me, which feel SO much more sturdy than the Wyatt one..I can flex the Wyatt fork in wards EASILY, but the Soma barely flexes. After he tests rides it I will be able to snag photos of the damaged fork for you guys.

 

[Kemosabe70]

Hey people here’s a banana for scale.

 

[Balmorhea]

Hey people here’s a banana for scale.

That gives me a good sense of how big the socks are.

 

[Kemosabe70]

Long time no post...

So I’ve got a phase runner wired up to the cycle analyst and I’m having some issues. After accelerating for a while I’ll get a throttle error and the motor stops accelerating, after a second or two I can accelerate again. Any tips on how to fix this?

Also, I’ll post some more pics soon!

 

[amberwolf]

What happens if you set the CA's throttle mode to "bypass"? That feeds the throttle voltage straight thru to the PR, so that nothing in the CA is messing with it.

If that works, you can be fairly certain it is a CA setting in the throttle processing menus, and can work with it from there.

If it doesn't work, it's probably something in the PR settings (it's a little complicated to setup, and has to be setup for each different motor and system; it's not plug and play like generic controllers).