Which PAS sensor do I need?

[Martinonwheels]

Dear group, I'm shortly to be getting a Yose Power kit for my old bike so why I'm waiting I thought I'd do the old bike up which included removing the crank arms. That's when I discovered they're not the usual square ones but something o think they call ISIS.
I know that the supplied PAS sensor won't fit. I think I have 2 choices. One is a 2 part sensor on the non drive side but when the crank is on I've just about a 5mm gap plus the shaft is about 22mm round. The other option is a 2 part sensor which would fit onto the chain wheel as the bcd would match up. So chaps, what does your collective experience say is the correct option. I've added some photos for clarity.
Thanks

 

[matthewslack]

That red chainring looks like a narrow-wide type, intended for a 1x gearing setup.

 

[Martinonwheels]

It is indeed, but if I fix the little silver chain wheel to it the chain wheel PAS would fit onto it.

 

[matthewslack]

As a mid-drive rider I can't answer your main question from direct experience, but I have read many times that chainwheel side PAS is better protected.

 

[saneagle]

Dear group, I'm shortly to be getting a Yose Power kit for my old bike so why I'm waiting I thought I'd do the old bike up which included removing the crank arms. That's when I discovered they're not the usual square ones but something o think they call ISIS.
I know that the supplied PAS sensor won't fit. I think I have 2 choices. One is a 2 part sensor on the non drive side but when the crank is on I've just about a 5mm gap plus the shaft is about 22mm round. The other option is a 2 part sensor which would fit onto the chain wheel as the bcd would match up. So chaps, what does your collective experience say is the correct option. I've added some photos for clarity.
Thanks

You can use any one you want. All you have to do is drill or dremmel out the hole to the right size. ISIS cranks are normally a bit tight for room, so you might have to drill it right out and glue it to the inner chain-ring.

 

[Martinonwheels]

You can use any one you want. All you have to do is drill or dremmel out the hole to the right size.

The 2 part ones that clip over the crank shaft all seek to have an internal diameter of around 15mm but as you know my bike crank shaft is 22mm. Would that not be too big a difference to allow me to drill or dremmel?

 

[saneagle]

The 2 part ones that clip over the crank shaft all seek to have an internal diameter of around 15mm but as you know my bike crank shaft is 22mm. Would that not be too big a difference to allow me to drill or dremmel?

I always drill them out to 25mm for Hollowtech cranks, which is the only type I'd use.

 

[Martinonwheels]

I always drill them out to 25mm for Hollowtech cranks, which is the only type I'd use.

Sorry, do you mean on the chain wheel side?

 

[thelarkbox]

Fwiw my bikes crank axle is a tad wider then the 17mm optimum for the default 1 piece pas sensor supplied with the yose kit resulting in the sensor spinning with the pedals until the cable snagged and secured it in each direction, delaying both assistance starting and overrun when pedalling stopped.

I tried filling/sanding out the softer plastic housing of the sensor to fit better but killed the sensor in the process somehow, the solution was to fit the alternative crank right (chain wheel ) side sensor.

 

[Martinonwheels]

Thank you, I was leaning towards a crank side PAS. My thinking is that if i got the type that fits to the chainwheel at least its held fast and should be a fit and forget solution .

 

[saneagle]

Sorry, do you mean on the chain wheel side?

I normally fit Hollowtech ones on the left side, though I did one on the right side. I have some photos from the pioneering days of 12 years ago here, posts 5 and 15 for the right side:

Rocky Mountain Element Conversion

I started the conversion today. This one will have one or more novel features. which I'm still trying to work out, so might be a bit slower than what I normally do. I snagged the bike for £380 and the kit cost about £500 including batteries, so I'm hoping to keep the total to less than £1000...

www.pedelecs.co.uk

and here post#3 for left side:

Rocky Mountain Conversion with Xiongda Kit

I like my Xiongda motor, so I decided to build a decent bike with one. My £5 Trax bike is OK, and I enjoy riding it, but I have this frame sitting around, and you can't beat decent suspension for a long ride. The Xiongda motor is about 150mm wide, so the first task is to stretch the frame. I...

www.pedelecs.co.uk

 

[Martinonwheels]

Thank you, they were interesting threads. I dont want to have to remove a lock ring to fit a bracket so that leaves two options. Drill out the 2 piece one and use a separate sensor or use the one designed to fix on the small chainwheel, which is probably the neatest option.