lhill 

I have been looking at ebike conversions for either my hybrid or vintage steel road bike. I would like your learned opinion on whether or not you think I could safely mount a small front hub motor on my old Peugeot or are the front forks too weak to handle the stress. Thanks!

surveyor6

I think your good ole steel peugeot fork would easily handle a 24v 250w hub motor. I would get a rear wheel for anything more powerful than that.

kahn

You could inquire with the following shop. They converted my bike to front hub. I will add that a front hub does change the handling dynamics of the bike and made it more twitchy. They sell the kits or do the conversion.

https://www.bikeswift.com/

lhill 

Thank you both for your help! I will continue researching the systems and who knows….

lhill 

Another question, when the max speed is given for a mid-drive system, like 25kph for example, how does the system know what gear you’re in and what your actual mph is? Thanks!

kayakindude

How much assist are you looking for? I think the motor/system can be tailored to the that answer. If it's just hill assist or extension of range without comprising the handling then 250 should do it. Also don't worry too much about the handling, whatever change it may have you will adapt to in short order. I have folders, tandems, road, and mountain...no issue switching between the styles.

lhill 

Thanks kayakindude, I was just trying to understand how a mid motor works. The motor just spins the cranks without regard to what rear cog the chain is on, correct? If the motor spins the cranks at 90 rpm with the bike in 4th gear than we’d be moving right along. But if the bike is in 8th gear at 90 rpm we’d really be flying. So, how does a Class 1 motor limit bike speed to 20 mph? How does it know?🤔

2old

The speed specified for a mid is that at which it stops providing assistance. You can go faster, but you're on your own.

andychrist

You program the display with your bike’s wheel size, just as you’d do with any bike computer. Hub motors have built-in speedometers but mid drives utilize a remote speed sensor.

lhill 

Thanks all for your helping me understand about ebike systems!