Suntour hesc freehub body replacement/repair advice

tim25

Pedelecer
Nov 21, 2020
39
3
Does any body recognize this free hub system? is it available in another name? this holds a 9 speed cassette. This had six threaded screw holes about 4mm in diameter to screw into through the motor cover plate. It comes from a 250 watt suntour hesc motor. There appears to be no spares available

I suspected the motor was not working because the cassette flywheel is locked open both ways due to water and dirt.

i began to apply a thin oil to the freehub, till it began to come loose, loose enough for me to hear it sounded like crunching metal...

One of the Pawls had come loose slightly and the spring, bent a little out of shape .
I have reshaped the spring wire and filed the pawls back into a sharper shape as they showed significant wear.

The freewheel now sounds and works ok and the motor is kicking in as a result of the torque applied to the crank. which is a good result.
However the toothed socket, the pawls grip into also showed significant wear and much more difficult to repair. A replacement would be much better.

Halfords can only supply a rear wheel complete and told me the freebody is a sealed non serviceable part. I Emailed Suntour directly and was told swiftly that for my own safety they could not supply me with the part.

It surprises me that you would throw away an entire wheel with hub motor when the freewheel fails? this must be a common problem for many halfords e bikes as they all seem to use the suntour Hesc motor, I see the motors That TBK supply offer replacement covers with cassettes built in. Suntour dont. Not a good example of our green economy ?

Its my intention to buy the controller and motor from top Bike Kit for my new conversion bike but ive allways been keen to try and fix broken bikes... that and old guitars.

Anyway, i would like to find a suitable replacement or at least perhaps a very similar one that i could canabalise / adjust to fit.

any ideas greatly received

Tim1 freehub body attached to motor axel and screwed to motor cover with 6 screws (Copy).jpg2 side view freehub body attached to motor axel without motor cover (Copy).jpg3 freehub body attached to motor axel motor cover off (Copy).jpg4 spring and pawls showing wear to the tips (Copy).jpg5 freehub body with pawls and ratchet socket ring (Copy).jpg
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,918
8,533
61
West Sx RH
Suntour/Halfrauds don't want you to repair instead sales and making money is their game. For the two stage reduction nylon gears one can carefully measure them and the tooth count to if they can be bough as individuals on other sites, but one may have to think of getting them 3D'd to replace or even have them machined out of steel.
It looks more like a case of the pawls that are worn, though they might have slightly worn the socket part it may be ok with brand new pawls. One would think the pawls are generic so maybe look at DTSwiss ones to see if they match, SJS Cycles use to have a good selection. The socket if warn would need machining for a replacement, but should be made of harder steel.
AKM models on Topbike have the freehub fully integrate din to the side plate so unlike the Suntour isn't removable. Some where one would think there must be some spare hubs that have been junked or replaced but getting hold of them is another issue, if one had an insider contact at Halfrauds then it may be a route to getting hand son a couple of defunct hubs to strip for spares.
 

tim25

Pedelecer
Nov 21, 2020
39
3
Suntour/Halfrauds don't want you to repair instead sales and making money is their game. For the two stage reduction nylon gears one can carefully measure them and the tooth count to if they can be bough as individuals on other sites, but one may have to think of getting them 3D'd to replace or even have them machined out of steel.
It looks more like a case of the pawls that are worn, though they might have slightly worn the socket part it may be ok with brand new pawls. One would think the pawls are generic so maybe look at DTSwiss ones to see if they match, SJS Cycles use to have a good selection. The socket if warn would need machining for a replacement, but should be made of harder steel.
AKM models on Topbike have the freehub fully integrate din to the side plate so unlike the Suntour isn't removable. Some where one would think there must be some spare hubs that have been junked or replaced but getting hold of them is another issue, if one had an insider contact at Halfrauds then it may be a route to getting hand son a couple of defunct hubs to strip for spares.
To my untrained eyes the gears look and sounded fine, smooth and quiet'ish. The machining of the toothed socket is beyond me . the restored pawls seem to work ok, i did buy some spare pawls from SJS on the off chance, they looked really similar, sadly a bit larger than mine . I was hoping the freehub body might be a generic part used in other motors?
 

Scorpio

Esteemed Pedelecer
Apr 13, 2020
372
164
Portugal Algarve (temporary)
Hi Tim,
Just for info my first ebike project was trying to fix a worn & broken hub - I now know several makes of hub have the same dimensions, and yours looks the same.
You might find it easier to source a replacement (used?) hub rather than trying to find specific parts to repair yours.
In the end I stripped my original wheel and replaced the faulty hub motor with a new-but-bought-in-error hub, then rebuilt the wheel using my original spokes & rim.
https://www.pedelecs.co.uk/forum/threads/kemp-starley-dutch-town-bike-out-of-hibernation.37181/post-594287

A possible solution (but it has a screw-on fitting so your existing casette won't fit) maybe ask if one of these hubs is still available? https://www.pedelecs.co.uk/forum/threads/wanted-yosepower-36v-350w-26-rear-cassette-hub-motor-just-motor-or-complete-26-wheel.37670/post-559880

or https://www.pedelecs.co.uk/forum/classifieds/e-bike-parts.175/

also one of the regular posters on here (maybe @vfr400 ?) is moving house soon and has a lot of spares for sale but I can't find his advert. Edit: https://www.pedelecs.co.uk/forum/threads/clear-out-all-sorts-of-stuff.40447/

Hope you find something that works for you :)
 
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tim25

Pedelecer
Nov 21, 2020
39
3
Update:

Halfords did supply me with a new motor cover plate with the free hub attached. a doddle to fit. and swapped out the large bearing on the other side of motor, all seems to work ok... im very happy to be able to fix it!
On the whole “Halfords” and “moore and large” (their parts supplier) were very helpful, Although I did need to push the process along a bit. And join the dots for them. “Suntour” were completely useless!

I now get about 18mph ish with the new kt controller. I have had to move the new controller onto the rear rack because its too large to fit in the original frame space.

i think the controller T09S 36V/48V450W-500W Torque Simulation Sine Wave Controller is drawing more amps than the stock battery bms can provide so the system is turning off. If i turn it back on and go easy on the throttle and limit to PAS 4 it will go very well and does not switch off. Ive tried messing with the max amps in the C settings but the result doesn’t seem any better. (Seems to cut the power to motor instead of switching off)but still loses power.

Ive had a plan to use my 18v Makita tool battery packs to power the bike for a while now as I have several and they all seem good with a built in bms and fast charger.

I already have the stock 36 volt / 8.5ah battery and have added a booster battery in series to add a further 12v using a 20 amp buck converter to step down the voltage from 18v giving me 54v total ( 12v + 42v ) top bike kit recommended highest voltage to be 54.6v for this controller 54v this gives me a great boost in power and speed up to about 23-24mph max (for private road use)

Questions :

1: I have read many threads saying using 2 batteries of different voltage is very bad and will ruin both batteries! Whats the verdict here?

2: What is the best way to monitor the battery using a multi-meter to find out whats actually going on in use?

I have a power level indicator on all batteries so have been monitoring them to not let either run out.

I have been charging both at the same time with its own charger and with the principle that the booster will run out first ( picture shows 2 boosters in paralell on back rack but ive found 1 works best)and I will charge them at the same time before the booster gets too low. ive tried a low voltage alarm but cant access the individual cells on the tool batteries so only can show the total of 12v on the alarm display.

3: Do you agree the maximum voltage would be 54.6 allowable on the KT T09S 36V/48V450W-500W Torque Simulation Sine Wave Controller. Could I push it to 60v?
That would allow me to use 3 x 18v Makita batteries as my main battery)( max v 60v charged)? Or would this be too risky to blow the controller?
 

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vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
You should search Endless-sphere for threads about running those controllers on 52v. I know there were some problems in the beginning. nothing burned, but the software didn't work right. I can't remember the details. I can't see 60v being OK, unless you switch to the open source firmware, which might be able to deal with it as long as the capacitors are rated high enough. I've got a feeling that they'll be 63v, which is too low, though I have had the bigger 48v KT controllers before that had a bridge inside for 60v, so it's always worth looking inside.

To put batteries in parallel, their output voltages must be close because they'll immediately try to equalise, which could mean masssive currents flowing between them, which could damage the BMS and/or the cells.. never leave them connected when charging because one will charge the other through the discharge wires, which will bypass the charge safety controls. You can do it if you use blocking diodes.
 

tim25

Pedelecer
Nov 21, 2020
39
3
Hi VFR400,

thanks , i will hunt around on endless sphere also for info on the controller. I think open source firmware feels beyond me.
I believe i have seen cylinder shaped things looking like a compacitor with 63v on them inside the controller.
perhaps ill have to stick with the 54.6 max charge im using now, Ive seen some step down buck convertors that will reduce 60v to 54v, just trying to avoid spending any more money and use what ive allready got, as i said before it seems to be working quite well and im enjoying it so far.

i did read about one guy who used something called a schottky diode or similar name to avoid tranfer form battery to battery.

Do it take it that when used in series voltage variation is not a problem ? apart from the allready discussed lack of low voltage cut off problem and draining the battery too low
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
Series is no problem. Just watch the low voltage. In theory, the BMS should cut-off the battery if the voltage goes too low, but I wouldn't rely on that.
 

holloway3232

Just Joined
Jan 14, 2022
1
0
Does any body recognize this free hub system? is it available in another name? this holds a 9 speed cassette. This had six threaded screw holes about 4mm in diameter to screw into through the motor cover plate. It comes from a 250 watt suntour hesc motor. There appears to be no spares available

I suspected the motor was not working because the cassette flywheel is locked open both ways due to water and dirt.

i began to apply a thin oil to the freehub, till it began to come loose, loose enough for me to hear it sounded like crunching metal...

One of the Pawls had come loose slightly and the spring, bent a little out of shape .
I have reshaped the spring wire and filed the pawls back into a sharper shape as they showed significant wear.

The freewheel now sounds and works ok and the motor is kicking in as a result of the torque applied to the crank. which is a good result.
However the toothed socket, the pawls grip into also showed significant wear and much more difficult to repair. A replacement would be much better.

Halfords can only supply a rear wheel complete and told me the freebody is a sealed non serviceable part. I Emailed Suntour directly and was told swiftly that for my own safety they could not supply me with the part.

It surprises me that you would throw away an entire wheel with hub motor when the freewheel fails? this must be a common problem for many halfords e bikes as they all seem to use the suntour Hesc motor, I see the motors That TBK supply offer replacement covers with cassettes built in. Suntour dont. Not a good example of our green economy ?

Its my intention to buy the controller and motor from top Bike Kit for my new conversion bike but ive allways been keen to try and fix broken bikes... that and old guitars.

Anyway, i would like to find a suitable replacement or at least perhaps a very similar one that i could canabalise / adjust to fit.

any ideas greatly received

TimView attachment 41120View attachment 41121View attachment 41122View attachment 41123View attachment 41124
did you have any trouble getting the freehub off the motor? im trying to do the same to mine to clean and regrease the pawls but having a load of trouble trying to get the freehub off. Have had a few carrera e bikes over the years and they always seem to come off fairly easy. currently got a 2019 crossfire e
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
1,855
1,343
Hi VFR400,

thanks , i will hunt around on endless sphere also for info on the controller. I think open source firmware feels beyond me.
I believe i have seen cylinder shaped things looking like a compacitor with 63v on them inside the controller.
perhaps ill have to stick with the 54.6 max charge im using now, Ive seen some step down buck convertors that will reduce 60v to 54v, just trying to avoid spending any more money and use what ive allready got, as i said before it seems to be working quite well and im enjoying it so far.

i did read about one guy who used something called a schottky diode or similar name to avoid tranfer form battery to battery.

Do it take it that when used in series voltage variation is not a problem ? apart from the allready discussed lack of low voltage cut off problem and draining the battery too low
Two threads yesterday were talking about parallel batteries and diodes, probably in the first two screens of 'what's new' now.

Read up about 'ideal diodes'. They do the same job as Schottky diodes with only a tenth of the losses. You need two, one on the output of each parallel battery, so that highest voltage battery will provide power and will not backfeed the other. If you think about plumbing, these are electrical one way valves.

The parallel batteries need to be the same nominal voltage. You cannot put a 36V and a 48V in parallel. So three Makitas in series cannot then be paralleled with the existing 36V battery.
 
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tim25

Pedelecer
Nov 21, 2020
39
3
did you have any trouble getting the freehub off the motor? im trying to do the same to mine to clean and regrease the pawls but having a load of trouble trying to get the freehub off. Have had a few carrera e bikes over the years and they always seem to come off fairly easy. currently got a 2019 crossfire e
no it came apart ok once i had soaked it in light oil due to being completely stuck due to dirt first removed the sprocket, then the axel nuts, perhaps the circlip in the free hub body, cant remember exactly as a while ago but ended up removing the whole top plate of the motor and removing the motor from the hub and the free hub came straight off after screws have come out, i do have photos of the process
 

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Peter A E Smith

Just Joined
Feb 18, 2022
1
2
I too have had problems with my Suntour HESC motor freehub namely warn pawls resulting in sporadic loss off drive. Like you Halfords told me the freehub is a none serviceable part and I would need a new motor at £320.00, Bullshit.
I emailed SR Suntour and they put me on to Moore Large and Co and they said they would happily supply Halfords with a new freehub and flange for them to sell to me.
In the meantime I managed to source an almost new faulty motor with a perfectly good freehub and side plate and I have now carried out the repair myself by simply removing the two chrome nuts on the axle to release the freehub then removing the six chrome star screws around the side plate to release it from the motor body. After applying a little light grease to the pawls I simply reversed the process to install the new parts.
job done and if I can do it anyone can.
 
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atıllae90

Just Joined
Jul 13, 2023
3
2
in case someone still has issues whit freehub pawls I have replaced mine whit
DT Swiss Service Kit for 3 Pawl freehubs
and I have made about 300+km since with no issues at all.
 
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rogers827

Finding my (electric) wheels
Sep 28, 2019
10
1
in case someone still has issues whit freehub pawls I have replaced mine whit
DT Swiss Service Kit for 3 Pawl freehubs
and I have made about 300+km since with no issues at all.
I needed to replace the freehub pawls on my HESC motor so took this advice from atiiiae90. Unfortunately, the kit is not a direct replacement for the model of moter that I have. The profile of the pawls is correct but they sit about 1.5mm proud when fitted. I had to dress them down somewhat to make them fit (see photo). Take more off the bottom face to ensure the retaining groove lines up correctly. Also the retaining spring ring diameter is too small. It only just covers all 3 pawls, (2mm overlap only on 2 of the paws). I have fitted it for now but will look for a replacement.
 

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