Advice for cruiser bike build

[scoobydrew]

Hi all,

I'm after a little advice please. I've built an ebike previously, based on an old mountain bike with a 500W rear wheel Q128 kit from BMS. This has been reliable although I have recently ruined the batteries by not looking after them - my own fault as I didn't disconnect them properly and over discharged the lipo's. So... time for new batteries and a new bike.

The bike will be used for commuting to and from work - this is all road, although with a reasonable 1.5mile long hill on the return journey. Total round trip is 20miles. Currently with the 500W Q128 I use approx 3500mah @ 48V lipo, although this is with fairly hard pedalling. The Q128 manages the hill without overheating at around a speed of 16mph and tops out with fresh batteries and frantic pedalling at probably 24mph.

I am looking to up the power level somewhat to reach a cruising speed of approx 30 - 35mph. I appreciate that at this speed, my pedalling input will be limited. I would like to build a good looking bike which still looks like a bike, without loads of batteries, wires and motors everywhere. It is also important that it is reliable. I can charge my bike at work as I can monitor the batteries constantly at my desk.

Budget is somewhat limited as I need to partially justify the outlay by making savings in fuel costs, so it will need to 'payback' if possible.

My thoughts so far are as follows:
Simple cruiser style bike (https://www.amazon.co.uk/Bermuda-Blackster-Cruiser-kickstand-mudguards/dp/B00XU7SP1Q/ref=pd_sim_sbs_200_4?ie=UTF8&psc=1&refRID=QYXR06MBFV2G5JK45HM8)
1500W DD rear wheel kit (http://www.ebay.co.uk/itm/LCD-48V1500W-Hi-Speed-Electric-Bicycle-E-Bike-Hub-Motor-Conversion-Kit-26-rear-/191859703745?hash=item2cabbabfc1:gvQAAOSwqfNXkVNa)

I would probably change the bars and seat to give it a more 'board track/vintage' look. The controller would be mounted in the frame triangle, probably in a frame bag (with plenty of ventilation holes). I've obviously given this some thought but would appreciate your input on the following:

Would the steel frame hold up to the task?
Any ideas on what the battery consumption would be like, moving from a Q128 500W to a 1500W?
I already have some 26x2.5" big apple tyres. Would a rigid frame and forks still be OK for street riding at the higher speed?
If front suspension would be best has anyone used this type of fork previously and if so, are they any good? (http://www.ebay.co.uk/itm/26-Classic-Straight-Spring-Fork-beach-cruiser-lowrider-bike-fork-153731-/282077461842?hash=item41ad207d52:g:dEgAAOSwDlBTweia)
Would it be necessary to upgrade the brakes? I would like the look of a hub brake on the front, which would also fit with the above fork if replaced. Braking would need to be good/effective but I will not be doing long decent's and overheating the brakes etc - just need to stop in an emergency. Low maintenance of a hub is also appealing.

Many thanks guys - as always, your thoughts and comments will be appreciated!

Cheers

Andy

 

[knox1138]

Augh! No! That springer fork is not strong enough for a bike with a motor. I used to have one on my motorized cruiser, and it would flex alot. Like, and uncomfortably large amount. Other than that you're good to go.

 

[scoobydrew]

Augh! No! That springer fork is not strong enough for a bike with a motor. I used to have one on my motorized cruiser, and it would flex alot. Like, and uncomfortably large amount. Other than that you're good to go.

Thanks - that was my concern but I haven't got any experience with them so thought it best to ask. Do you run just a solid fork now or have you swapped to a mountain bike type fork.

Cheers

 

[dogman dan]

First thing,,to go 35 mph, you need brakes.

Here's my35 mph cruiser for an example. It runs on 48v 40 amps controller, for 2000w.

Maybe more than you planned on, but I wanted to have up to 100 mile range, carry cargo, tow trailers, etc. So I needed some big bags to carry big batteries.

But the points I want to point out are that the bike has 7 speed rear gears. That's what you need to start with, a 7 speed cruiser with two rim brakes at a minimum.

The cruiser you picked is a coaster brake bike, inadequate for 35 mph. The brakes, no worries about steel cruiser frames. My bike started out as the same type of bike, but I extended the rear 9 inches, and the extension has a disc brake mount built in. Then I welded a disc mount to the front fork.

If you want to put an MTB fork on a cruiser, then you need a cruiser that can fit a decent one. you need a 1 1/8 headset frame. So the budget just blew out, if you need a better bike like an electra townie. But it might be well worth the budget. BTW, townies come with a front shock fork, then you put the motor on the rear.

my bike was built on a budget of $250. $100 for the bike,, $50 for some disc brakes, and $100 for the welder. Not counting the motor stuff, just bike.

But the same $250 budget can get you a much higher quality cruiser, especially a used townie.

 

[mettzman]

Dual Cutes on a solid steel cruiser frame would be fun, 22amp continuous for each and a 50amp continuous 48-52v battery. Top speed would be similar but off the line and hills would be impressive. Over 30mph and the wind drag is intense, especially sitting upright. Batteries get bigger for that for sure. I wonder if the lower speed would bother you if you could keep your speed up on hills. Theres always MAC motors, I'd buy from Cellman before buying on eBay...Bafang hubs maybe. 35mph with a DD hub is entry level hot rodding....get out your wallet.

 

[scoobydrew]

Thanks for the feedback everyone. Plenty of food for thought - will do some further research and will let you know what I come up with!

Cheers

 

[dogman dan]

Dual any motor will definitely result in a cruiser that can tackle any hill, even very loaded down. Once you get to 1500w and above, you just don't fear any paved hill.

But improving the brakes is the best thing I did to my cruiser. Just welding on a front disc mount to a typical cruiser fork will do a lot of good. And as welding goes, it's pretty easy to do.