PAS for Sprocket Rotation-query.

[Bikes4two]

• After 2 years being very satisfied with my TSDZ2 machines I am out of curiosity in the process of doing my first (front) hub conversion to see what ebike life is 'on the other side' of the argument (hub vs mid drive).
• So only some of the items are with me as I await the slow boat from China but I do have a PAS designed for mounting on the chainring side and is specifically for Hollowtech 2 type of chainsets (I actually have Campag power torque but they are of similar dimensions).
• This PAS is designed to mount to chainrings of around 22 teeth (74 PCD?) which is smaller than currently fitted (110 PCD) but I'll be making a 3d printed adapter to deal with that issue (hopefully).
• However, I'm aware that the Mahle X35 and Cytronex systems use a PAS that sits adjacent to the rear sprockets on a derailleur system and I'm wondering should my chainring PAS idea not work out, whether a sprocket PAS could work instead?
• QUESTIONS
  - I've no idea what type of signal comes from the sprocket PAS and whether it is compatible with the PAS input on a standard KT sine wave controller
  - and of course where you might buy a sprocket PAS sensor (that is, without selling body parts to get a Mahle part!)

Any knowledge about this anyone?

The pics below are the PAS for Hollowtech 2 and the Sprocket PAS on a Cytronex bike.

 

[saneagle]

• After 2 years being very satisfied with my TSDZ2 machines I am out of curiosity in the process of doing my first (front) hub conversion to see what ebike life is 'on the other side' of the argument (hub vs mid drive).

That's not going to give you the ideal hub-motor experience. Why don't you get a normal rear motor if you want the ideal?

 

[thelarkbox]

Pretty sure your magnet ring and sensor will be fine, if your lcd manual and Chenglish comprehension are similar to mine it might just be easier to cycle through the 4 or 5 pas sensor options to test than trying to understand the manual.

just try to mount the ring 'straight' and the sensor so its a few mm away from the rotating disk.

 

[Nealh]

The Mk1 Revos friction drive uses a sprocket PAS detection , then later ones used a conventional two piece PAS . Whether the controller programming was changed or it was a simple swap of one for the other I don't know.

 

[thelarkbox]

btw if you just need to bulk up the diameter of the hollowtech axle, gaffer tape is a pretty easy tear to fit the width and wind on solution thats gonna be 'weatherproof' for long enough for a proof of concept trial if not longer

 

[Bikes4two]

That's not going to give you the ideal hub-motor experience. Why don't you get a normal rear motor if you want the ideal?

I understand 'the love' folks have of rear vs front hubs but I've a number of objectives here:

1. Minimal cost - the front hub is a 2nd hand Swytch bike motor bought for the princely sum of £58 in a 700c wheel, so a bargain and I've ridden a Swytch bike and am happy with the motor's performance.
2. I want as stealthy a fit as possible and am looking to compare what I achieve with my cycling buddies who have lavishly bought the Cytronex (£1,000 a time).
3. I'm mounting the wheel/motor in carbon forks (on a full Trek Madone which I've not ridden for years due to health reasons) as I believe this will be fine for my style of riding - I'll soon find out.
4. If the motor delivers power in the way I'm hoping, I will be re-building the motor into a 26" wheel to try on our tandem (minimal assist and front hub needed as Rohloff IGH on rear and no room for a mid drive).

I'm not expecting to get over excited about a front hub vs the TSDZ2 but I'm open minded and maybe I'd look at a rear hub later.

 

[Nealh]

Jumping straight to a front hub one may ponder what the hub fuss is about.
Before coming to any conclusions of hub vs mid motor one will need to experience a rear hub conversion as well using a KT system.

Lightweight or those with higher internal gearing ratios make the choice easier imv. .

I for one love my light weight front G370 on the Cotic Roadrat , the difference between it and the front BPM I had on the Norco is night and day .
The BPM was 2.5 X the weight and much more powerful, the BPM had too much power and torque to make the ride truly comfortable and steering was affected by torque steer. None of this occurs with the G370.

I had the lishui controller with the BPM and the KT with the G370, KT is far better where one can control the power needed .

 

[Bikes4two]

QUESTIONS
- I've no idea what type of signal comes from the sprocket PAS and whether it is compatible with the PAS input on a standard KT sine wave controller

I found a very useful article by Grin technologies about some of the different types of PAS sensors there were at the time of the article (LINK and last updated 2022) and no doubt there are others that have come along in the meantime. Interestingly the Grin article didn't say anything specific about sprocket PAS sensors.

The upshot is that I'd better get the PAS sensor that I have to work!

@Nealh

I for one love my light weight front G370 on the Cotic Roadrat , the difference between it and the front BPM I had on the Norco is night and day .

After reading many of your positve comments about the G370 over the years, I would have given that motor serious consideration if I could have found it in a shiny polished steel finish like the Swytch motor (no, I didn't want to paint a black one silver ).

The Swytch motor is the Aikema 100sx apparently which albeit around 0.2- 0.3 Kg heavier than the G370, delivers a bit more toque it would seem, although how much (a) the online figures can be relied upon and (b) there's much of a practical difference, I know not.

Oh yes, the G370 comes in at about £130 before posting and any tax (Top Bike Kit), so rather a pricey alternative to my ebay purchase.

 

[saneagle]

A front hub is OK with low power.

The Cytronex sprocket sensor is a magnetic proximity switch that needs special electronics to use as a signal. It won't work with a KT controller. I can't see why you's want to use that one when a normal pedal sensor works perfectly.

You threw us when you said that you wanted the ideal hub-motor experience. You should have said that you want to see whether a front hub-motor is any good, when you get it for nothing.