Advice on replacement crankset for Torq

[Manchego]

Unfortunately I've stripped the thread on my right pedal (don't ask) and so need to replace the chain wheels and cranks. I could get a replacement from 50cycles but I'd prefer to get a higher quality replacement fitted - perhaps giving me a slightly lower gearing too. I know a few people have tweaked their Torqs and i wondered if anyone has any advice they could give me?

thanks

 

[flecc]

Replacing the 52 tooth chainring with a 48 tooth will make the 8th gear the same as your present 7th gear Manchego. A 44 tooth will drop it approximately a further gear, to around your 6th gear.

Some have gone a bit extreme with a 38 tooth, but that's not always suitable if a Torq is derestricted since it's then difficult for many to spin the pedals fast enough to keep up with the bike's motor on the flat.

I'll leave it to others to suggest cheap sources for these, a few having found some very low prices.
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[Manchego]

thanks Flecc - I'll give that a go

 

[Ian]

Hello Manchego,

I've have fitted a 38T chainring to my Torq, not quite as extreme as it sounds as I have an 11T top gear, it makes for a rather low low top gear but suits my short legs and riding style. I'ts not for everone though, something like a 44-48 as suggested by Flecc being more suited to most people.

The Prowheel cranks fitted as standard are high quality alloy forgings and there would be little to be gained by replacing your damaged right crank with an alternative brand, an identical relpacement would have the advantage of not needing to adjust the chainline and it should be possible to purchase just the side you need. The chainring is a separate item, a 5 bolt 130mm pcd Shimano type being required for the standard crank, available from 38T upwards. Stronglight branded chainrings are good quality and value, usually about a tenner for the smaller sizes although bargains can be had on ebay, my current Shimano 105 38T cost less than a fiver.. brand new.

 

[flecc]

Welcome back Ian, I hope you had an enjoyable holiday and the weather wasn't too unkind.

I had a couple of very busy days in here and you were very much missed, good to have your input again.
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[Ian]

Thanks Flecc, it's nice to feel wanted although it will probably take a couple of evenings to catch up.

 

[flecc]

Don't worry, I know the feeling of needing a holiday to get over the holiday.
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[Manchego]

thanks Ian - I've followed your advice and ordered a new right hand crank from 50cycles. I'll look into the chain rings separately - but from the sound of it a 48 might suit me best.

 

[JamesC]

I'll leave it to others to suggest cheap sources for these, a few having found some very low prices.
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Hello Manchego
I am using a Sugino chainwheel from this link on ebay:

Sugino alloy chainwheels (to fit Shimano Road chainsets - eBay Bike Parts, Cycling, Sporting Goods (end time 13-Oct-07 21:55:07 BST)

email the seller to check whether the number of teeth that you want is still available - 40, 43, 44, 46t & 49t are showing in the description, but it might not have been updated.

With regards to gearing, pages 49 and 50 of the "Just registered" thread carry lots of good advice.

James

 

[Manchego]

thanks James - very helpful
cheers

 

[Manchego]

Update - went for the Sugino 44, slightly shortened chain. Much better. Thanks for all advice
cheers

j

 

[Ian]

Thanks for the update Manchego, you can allways fit an increased range cassette if you want to take it further.

 

[JamesC]

Fitness improving on the Torq - cadence again

Thanks for the update Manchego, you can allways fit an increased range cassette if you want to take it further.

Ian
Torq users have enjoyed lots of discussion on the forum about gearing, largely based around the benefits of some lower gearing to allow the rider to contribute more useful effort on the hills.

Much of my riding is on flat terrain - to the north or east of Peterborough, a bridge can be as near to a hill as one gets !

The fens have lots to offer on a sunny autumn day, concentrating the mind on finding the most comfortable gearing to match one's level of fitness and natural cadence.

Riding the Torq in restricted mode, like any other ebike the speed of 15 mph (bit more with 37 volt Li ion, bit less with 36 volt NiMH) plays a big part in defining the base speed for a ride on flat ground.

In developing my fitness (bypass surgery etc), I have been surprised to discover the narrow range of leg speed that feels really comfortable over long distances.

For me, it is very close to about 70 RPM (not 60, not 80)

At this leg speed (cadence), I want to do a certain amount of work so I want a gear that is greater than the 15.5 mph provided by the motor.

Again, the range is quite narrow, but I find that lifting the speed to about 16.5 mph gives me some useful exercise whilst still sharing the work with the battery.

(Thanks to ITSPETEINIT for introducing me to * Front Page — www.arachnoid.com Bicycle Analyser)


To increase the range of the 8 speed gearing, I went for the Shimano HG30 cassette 11-32 T, using the original 12T top gear.

To arrive at my most comfortable (6th gear - 16 T) gear for the flat, I use a 45T chainring.

With Schwalbe Marathon Plus tyres (wheel diameter 27.44 inches) and a Cadence of 70 RPM, a 6th gear of 45/16 comes out as 16.1 mph using the Bicycle Analyzer.

Either side of this, 5th gear (45/18) is 14.3 mph and 7th gear (45/14) is 18.4 mph.


If I change to a 44 tooth chainwheel and keep pedalling at 70 RPM, then the mph comes much closer to "motor speed" at 15.7 mph and my physiotherapy becomes a little too easy.

As I get fitter, I will expect to gain a little more speed above the famous 15.5 mph, and may need a 46 tooth chainwheel if my cadence stays the same.



I hope this illustration shows the benefit of chosing one of the gears quite accurately in relation to the effort that the rider wants to make.

The forum is great at encouraging e-biking for a wide variety of reasons, physio being just one of them.

As 25 km/h (approx 15.5 mph) has been established as the standard motor speed unassisted, it would be interesting to hear if others have views on how best to gear for rider input.


James

 

[flecc]

I don't use restriction, both the the Torq based T bike and Quando based Q bike using the natural motor/battery capability.

Used in this way there's no absolute for gearing to suit me since since the motor run out speed changes with charge level. The Q bike's motor can run it to 18 mph initially, but that gradually declines and nearing the end of charge is down to about 15 mph. Likewise the T bike full/empty range is 24 down to 20 mph.

As a result I basically just swap by one gear during that decline to keep in my most comfortable long term cadence area, a bit higher than yours at around 75 to 80, though I occasionally like to spin at 90 plus for short periods just for the workout.

I have a hardly ever used megarange low at 42", but the main gear range starts high at 60" to 112" since the motor has 10% more power than standard. (The standard Torq has 58" to 122").
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[JamesC]

The Marathon Plus tyres are a great improvement that I would endorse for anyone.

At this wheel size and a cadence of 70, the standard Torq gearing offers 52/19 giving 15.6 mph or 52/17 giving 17.5 mph.

There is quite a substantial change in rider effort between these two gears if the throttle is held flat out in restricted mode.

Accurate throttle control is much easier with Flecc's throttle mod which I use, but on the open road an ebike will often be running at 15.5 mph unassisted.

Having a gear in between the standard gap improves the feel and I believe must help towards greater range from the battery.


In designing an ebike, how important is it to hit one of the gears just right for the rider input, when so much of the electrical aspect is focused on riding at a specific speed ?

James