Roadrat Alfine 8 with G370 hub build.

[Nealh]

As per the title, the build though may take a while as I am quite busy.
The tower scaffold has already been up and down twice and will be so a few times more this year and the bees are needing my attention alone without other distractions. The rubbish is building up as well due to the council tips being closed.

I have got hold of a Cotic small frame from an all steel Roadrat.
The forks are of no use as the calliper fitting is LHS.
The front derailleur is new old stock and picked it up off ebay for £5, I plan on going double up front for the Alfine as I did on the Kona Blast.


Head set badge nice.



As the forks are not of use I will replace them with a new steel set by Surly along with On One Mike swept bars, a bargain for about £12.


My first couple of jobs though will be to lace/build and true the Alfine 8 and G370 in to new 700c rims. Sokes will be my favoured ones Sapim Strong's 14g procured from the excellent services of Spokes From Ryan.

 

[Amoto65]

This looks really interesting, make sure you take loads of pics, love that frame.

 

[Nealh]

I will be posting new pics as I go along, though it won't be a rapid build.

 

[WheezyRider]

Looks like an interesting project. Are you going to have the Alfine 8 hub in the back and use the G370 as a mid drive unit? I like the handlebars. Should give you good control, a lot of the newer MTB handlebars are almost straight and I find them very uncomfortable.

 

[Nealh]

G370 front wheel drive.

 

[WheezyRider]

G370 front wheel drive.

Hmmm, not sure you'll like it. That's going to be a lot of power on the front end. I assume you're going to use 20amps at 48V? At max battery voltage, you've got over a kW spinning that wheel and not much weight on it. I've found even a low power front drive needs a fat front tyre to stop it losing grip on bends and in the wet, it's seriously not pleasant! That's when a hand throttle is very useful. With PAS, which is often likely to be on the highest setting, it could set you off at full power into a bend just by a slight turning the pedals...On loose gravel, forget it! I've recently gone back to rear wheel drive and it it so much better. However, I do like the idea of a geared hub, much nicer than a derailleur, which soon gets clogged with road dirt and crap and looses load of efficiency if not kept totally clean and lubed.

 

[Nealh]

I have a very good idea of how it will ride and feel as I have the more powerful & heavier front BPM at 20a, not had an issue with it on a 700c hybrid in all weather road riding or the latter mtb I tried it on for off road with 12s.
Never assume anything for now it will be 20a @36v, possibly later maybe 12s.

 

[WheezyRider]

I have a very good idea of how it will ride and feel as I have the more powerful & heavier front BPM at 20a, not had an issue with it on a 700c hybrid in all weather road riding or the latter mtb I tried it on for off road with 12s.
Never assume anything for now it will be 20a @36v, possibly later maybe 12s.

Ok, you must have good tyres

Looking forward to seeing the pics of the build!

 

[Nealh]

Front hub / wheel will in some situations will scrabble /spin for grip but it is how you apply the power, no use using high pas/throttle if wheel spin is evident. Low speed/gear will give higher torque and traction. No throttle on this build, tbh I don't use the ones I have fitted.

 

[Nealh]

Alfine 8 hub laced up and trued in to the new rim, rims are Belgian (I think) Ryde Z2000 quite cheap at £19.99 a pair and decent in design. I have them on my 700c CX bike and they put up with everything I chuck at them without issues.

As with all my hubs I tend to use a 2X lace, 266mm 14g Sapim Strongs for the 596 erd rim.


Bafang mini hub G370 also laced and trued in to the new rim.
264mm 14g Sapim Strongs for the 596 erd rim.
Tyres are 622 x 43c Panaracer GK /SK's, though 43c the actual tyre when fitted is 41mm.

 

[Nealh]

The G370 with its face plate removed.

The two step planetary gears give the 14.6 gear ratio.


Face plate with the outer sun gear and a film of grease.


Mr Tom keeping an eye on things, just to break up the bike theme.

 

[Nealh]

The Rat is starting to take shape now.
Wheels, forks fitted, steerer cut down and bars added.. Discs are on and crank set on, for now will go with single 36t to see how it goes when done.



Steerer currently set at similar height to my existing bikes plenty to come down if need be.

 

[Amoto65]

Looking really good, nearly makes me want to sell my Crossfuse and build my own(if I had the tech skills)

 

[Nealh]

I haven't decided yet where to place battery and 22a julet controller, despite the frame being a S the frame the triangle is a decent size. I have a pair of 8ah 10s lipo which I will press in service both give about 25 miles, I may have to ut my thinking cap on and construct a GRP triangle enclosure for all three items.

Front brake is fitted as is the PAS, need a new olive for rear brake hose as the rear hose line passes through braze on closed cable guides so have to cut the calliper end fitting off.
Seat wise will reuse a Lidl Wikitip saddle and have a pair Shimano SPD's with flats on one side.

 

[WheezyRider]

I haven't decided yet where to place battery and 22a julet controller, despite the frame being a S the frame the triangle is a decent size. I have a pair of 8ah 10s lipo which I will press in service both give about 25 miles, I may have to ut my thinking cap on and construct a GRP triangle enclosure for all three items.

Front brake is fitted as is the PAS, need a new olive for rear brake hose as the rear hose line passes through braze on closed cable guides so have to cut the calliper end fitting off.
Seat wise will reuse a Lidl Wikitip saddle and have a pair Shimano SPD's with flats on one side.

Looking really good!! Did you lace the wheels yourself?

Do you have access to a 3D printer? I used one so I could mount a 15Ah Silverfish style battery on my downtube. A lot more secure than any bottle holder mount and the entire clamp system only weighs 200g.

 

[Nealh]

Yes, build all my wheels.
No 3d. Oki

 

[Nealh]

Rat build slowly progressing, saddle fitted and found a CF seat post in the spares bin.



HDB's fitted, LCD4 in place and added a Nexus shift twist grip instead of the trigger shifter I have. Also added GP1's cut the RH one down with a craft knife.

 

[Nealh]

Currently fitted a 104bcd 36t China Brand SNAIL narrow wide ali chain ring and ali protector. When I get the rear hanger for the horizontal d/o's, I plan on fitting the double front 32/42t combo.
Ordered off AliExpress seller for £3.89 & £ 3.29 each, buy the same items on Ebay and they are 4 or 5 X the price or more each., arrived by post within 14 days.

 

[Nealh]

Like Kyle from the Black Forest I am also going to make a triangle box for my controller and 10s lipo's. Also have mocked up the stiff card box which will act as the moulds for the GRP, maybe in a weeks or two's time when I have a bit more time.
When cured and finished I can rattle can them for a livery to suit the bike, Black is the obvious colour but may look at the White, Grey and a bit of Orange as on the frames seat tube.

 

[Nealh]

For my battery/controller compartment I have designed it along the lines of the Aluminium and plastic case design from my Swizzbee for making in GRP.

The top section (center rib section) will have 2 or three layers of 300gsm matting applied to the exterior of the shape and will be approx. 80mm wide, this will form the main part of the box and the fixing to the frame.


The two lower sections are the side covers, GRP will be laid up to the inside of them with a barrier to prevent sticking. Grease proof paper acts as a very good barrier in the moulds, it leaves a super smooth finish to the exterior and simply peels off once the mould has cured. The covers will simply fit over the center rib section, attach ment is by use of simple press fit ' W ' buttons as in the Swizzbee design.

Center rib section sitting inside the LHS cover template, using this way of making the compartment the internal width can be anything from 80mm wide up to about 120mm. I'm aiming for about 90 - 95mm internal width, once the center rib is cured I can then think about adding shelf's/compartments to keep the controller and 10's lipo packs in place.




For the future when the lipo's are spent I will look at Samsung 50E 21700 cells as a power source, the 700 cycle charge/discharge age testing carried out on ES using 2.5a charge & 1a discharge cycling show them to be in the same class as the LG MJ1, M36 & HG2 with all maintaining at or above 93% of capacity.
The results for 50E I think were the most impressive as a charge rate of 3.75a was applied and discharge of 1.5a was applied. Following these four the Sam 29E wasn't far behind at 90%.
Sanyo/Panasonic were bottom of the class as was the Sam 35E & 30Q.
GA & 30Q below 85% capacity and the PF was worse less then 80% capacity after 700 cycles.