Damn... a beauty will be born. (26 to 27.5 conversion!?)

[BestBoy]

Today, I bought a used Carrera Valor 27.5 bike for £90 and I've moved my DIY ebike kit over from my crap 18 yr old steel MTN bike.

The hybrid shape has force me to put battery on the top bar but I kinda like it. Its kinda like a 'petrol tank'.
Its very cool. So, I'm mixing 26 inch DD rear hub motor with a 27.5 front wheel. I'm ok with the geometry but the back wheel doesnt meet the V brakes so I've only front brakes.

Can anyone explain if its possible to re-lace my motor hub onto the 27.5 original rear wheel that came with the Carrera?

 

[MadRhino]

Of course you can lace your motor in a 27.5 rim, but you should find a 36h for it is very unlikely that your original rear wheel is drilled 36h.

 

[MadRhino]

Of course you can lace your motor in a 27.5 rim, but you should find a 36h for it is very unlikely that your original rear wheel is drilled 36h.

 

[BestBoy]

Thanks!

So thats a pita! Just realising that the spokes numbers aren't the same.

Is there a 'standard' of sorts, where I can buy spokes that will fit a 36H 27.5 perfectly with my DD hub? I dont know what size the hub is but Im sure the 1000W hubs are all the same size?

 

[BestBoy]

Ok so £49.99 I can get a 27.5 with 36H. Thats not so bad...
Now, Im sure there must be a spoke length thats very specific to a DD 1000W motor on a 27.5 with 36H!?

 

[BestBoy]

Also,

This looks like it'd be awesome if I had any clue what size the hub was or where to measure it from.

http://www.ebikes.ca/tools/spoke-calc.html

 

[MadRhino]

You measure the hub from flange spoke hole to the opposite spoke hole.

The rim has an ERD number, giving you its exaxt dimensions.

A spoke calculator will give you the spoke length, according to motor and rim dimensions, along with lacing pattern, offset, dishing... that tou may need.

 

[BestBoy]

Thanks man.

So you can buy spokes that are a variety of lengths but all fit the same holes?

 

[wturber]

I think brake post extenders like this are generally used to put larger wheels on a bike. But I wonder if they can be used to do just the opposite? Conceptually, that seems reasonable. But I'm not at all sure if it is practical.

https://www.amazon.com/Cycle-Group-PX-BK14EXTEN-BK-Promax-Extender/dp/B00QICKB12/ref=sr_1_3?s=sporting-goods&ie=UTF8&qid=1535847891&sr=1-3&keywords=brake+post+extender

 

[BestBoy]

Yeah,
Ive looked at the potential for a brake post 'adapter' but I cant see it happening. Its all very tight in there. Not much space and you'd need an 'L' shape braket to move the pad lower. It just seems easier to make it a 27.5 rim... unless someones made a bracket already!?

 

[Tommm]

Simplest solution is to use regen to brake rear.
Changing to a bigger wheel will lessen your torque and make the wheel weaker and increase the stress on your frame. There is a reason high powered hub builds have 17" moto wheels (= below 24" bike wheel).

 

[BestBoy]

Thanks,

Yeah, but can my ebike 'voliamart' kit do re-gen braking!?

https://www.amazon.co.uk/Voilamart-Electric-Conversion-Intelligent-Controller/dp/B06XXQK2MD

 

[Chalo]

Yeah,
Ive looked at the potential for a brake post 'adapter' but I cant see it happening. Its all very tight in there. Not much space and you'd need an 'L' shape braket to move the pad lower. It just seems easier to make it a 27.5 rim... unless someones made a bracket already!?

You misunderstand the item wturber is talking about. Your frame is aluminum; the brake posts are steel and they're screwed into the frame with threadlocking adhesive. The adapters wturber linked to are designed to screw in to the same points that held the original brake posts, and then the posts screw into the adapters at a point 16mm up or down from the stock location.

The radius of a 27.5" rim is 12.5mm greater than that of a 26" rim. So moving the post down 16mm should bring the pad within the brake's built-in range of adjustment to fit a 26" wheel.

That bike is a department store BSO (bicycle-shaped object) that surely was never properly set up or adjusted to begin with. Save yourself some grief and have the thing professionally tuned up before it chews itself to pieces.

 

[BestBoy]

Ah ok cool. Ill look into the brake post extenders! Yeah, I'll make sure the bike is setup right. Thanks.

 

[999zip999]

We get those kits as cheap as 150.00usd complete. They my have a kit 27.5 for ?
As I payed 45.00 for spokes and 35.00 for a rim and them made a turing stand. The first wheel build I cryed I got it by the third build.. It's a lot of learning and with a heavy motor.

 

[Chalo]

We get those kits as cheap as 150.00usd complete. They my have a kit 27.5 for ?
As I payed 45.00 for spokes and 35.00 for a rim and them made a turing stand. The first wheel build I cryed I got it by the third build.. It's a lot of learning and with a heavy motor.

I feel that. That's why I advise folks not to make a hub motor wheel their first build. Wheel building is hard, and hub motors make it harder for a number of reasons. I also advise not to make your first wheel build something that you need for regular transportation. It's like making pancakes; the first one isn't usually what you were getting at.

It's still worth it to either build your own or have a pro do it for you, because the complete wheels that come with the kits are made poorly with the cheapest available parts (and usually the wrong diameter spokes). They're certain trouble.

 

[markz]

advise

Chalo, I am disappointed in you :lol:
What, no comment on 27.5 being

It's like a chump test for cyclists.

I will remember that!

26" is better at some things, 29" better at others. 27.5" isn't best at anything, and it was introduced specifically to make existing MTB owners buy a whole new bike in order to get it. Not coincidentally, rims and tires for 27.5" are more expensive than the same items in the other two sizes.

It's like a chump test for cyclists.

 

[markz]

advise

Chalo, I am disappointed in you :lol:
What, no comment on 27.5 being
How was it worded......

It's like a chump test for cyclists.

I see your reasoning though Chalo :wink:
21 and all :wink:

I will remember that phrase!

26" is better at some things, 29" better at others. 27.5" isn't best at anything, and it was introduced specifically to make existing MTB owners buy a whole new bike in order to get it. Not coincidentally, rims and tires for 27.5" are more expensive than the same items in the other two sizes.

It's like a chump test for cyclists.

PS I highlited, underlined, bolded and colored blue - A good point on 27.5 being more costly.

 

[999zip999]

Markz pass it over or under as I will take same. Yes 27.5 the hard number deal with the price of tires the price of tubes the price the rim everything special because all mountain bike riders need to feel special when they buy eight to $12,000 bike

 

[999zip999]

As for what you doing get the 26 inch rim hook it up to regen with a good enough battery and use it tighten the spokes to the rim and put it on the road for a while after a year 6 months or 2 years studying upgrade

 

[Chalo]

A good point on 27.5 being more costly.

It's generally true but there are a few exceptions. For instance, I discovered that the WTB ThickSlick (a really good street tire) costs the same in Mama Bear, Papa Bear, and Baby Bear sizes.

It probably doesn't hurt that the molds for that model of tire are comparatively cheap to machine, and the tire is popular. They don't have to worry so much about amortizing their tooling costs. But with everybody in the industry saying "me too" to 27.5", some folks are surely going to be left standing when the music stops.

GT Bicycles tried this kind of stupid marketing stunt in the 1990s, and got what they deserved. Unfortunately, in the year since then, the bicycle industry has gotten much more consolidated around pointless marketing stunts.
http://www.sheldonbrown.com/harris/tires/587.html

 

[markz]

marketing

consolidated around pointless marketing stunts.

They gotta rake in the money somehow, like any other product on the market: How to Maximize Profit!
Remember.....
3D tv's
Plasma tv's
what about them curved screens out now!
I know tv's are not transportation related, nor on topic for this thread.
But Chevrolet did have a truck with 4 wheel steer, for a year or two.
Undercoating

Early Adopters fall for anything.
Then they gotta keep that train moving along$$$$$$$$$$$$$$$$ chooo choooooo

I guess the good thing about 27.5 with disc brakes is you can then use a 26" wheel. Which was mentioned hopefully.
But yup, lets throw in a scenerio, small town, hicktown, bike packing, "Sorry sir, no 27.5" tubes or tires"

 

[wturber]

... They're certain trouble.

Maybe they are likely trouble, but certain trouble? I dunno. I just crossed the 4000 mile mark on mine this week. Maybe I'll start popping spokes tomorrow? <shrug>

 

[Chalo]

... They're certain trouble. [Chinese hub motor kit wheels]

Maybe they are likely trouble, but certain trouble? I dunno. I just crossed the 4000 mile mark on mine this week. Maybe I'll start popping spokes tomorrow? <shrug>

Well, let's just say that the ones I see in the shop are either in the process of unscrewing themselves, or the nipples are corroded to the spokes.

But most of the bikes that have them have come into the shop for some other problem. So I guess their owners don't think of them as trouble.

 

[neptronix]

Just keep in mind..
You will lose a little torque if you go up one wheel size.

I would just run regen for the rear brake. If you don't have regen, get a programmable controller where you can tune the regen strength.. and put a very very large rotor up front for safety purposes.

Worked very well on my 4000w build.