Does wheel size matter

[Bigfoot]

Looking for a e bike. Found a nice kalkhoff with belt drive. It has 25" wheels not the usual 28". The frame size suits me 6ft 2inch. Will the smaller wheels mean slower top speed more pedalling ? Or any other disadvantage?

 

[Nealh]

25" isn't a standard wheel size are you sure ?

 

[flecc]

Looking for a e bike. Found a nice kalkhoff with belt drive. It has 25" wheels not the usual 28". The frame size suits me 6ft 2inch. Will the smaller wheels mean slower top speed more pedalling ? Or any other disadvantage?

They are 26" wheels on many Kalkhoffs, not 25".

The assist speed and pedalling speed are not altered by the wheel size. The sprockets are chosen to give the same performance for both, regardless of 26" or 28" wheels.

There are tiny differences in rolling resistance and turn speed, but so small it's not worth bothering about.
.

 

[Bigfoot]

They are 26" wheels on many Kalkhoffs, not 25".

The assist speed and pedalling speed are not altered by the wheel size. The sprockets are chosen to give the same performance for both, regardless of 26" or 28" wheels.

There are tiny differences in rolling resistance and turn speed, but so small it's not worth bothering about.
.

The seller has now checked and there 28 in rims. Panic over. So without seeing or test riding the bike it is a 2018 with 1437 mls on the clock and a 500w battery. Seller doesn't know how to check battery power capacity. Nor do I. Is that mileage for the year a risky purchase without seeing it?

 

[Nealh]

What motor ?
If an impulse drive, give the bike a wide birth.
The impulse is plagued with errors/failures.

 

[Bigfoot]

It's a bosch active line plus on a kalkhoff agattu frame

 

[matthewslack]

The seller has now checked and there 28 in rims. Panic over. So without seeing or test riding the bike it is a 2018 with 1437 mls on the clock and a 500w battery. Seller doesn't know how to check battery power capacity. Nor do I. Is that mileage for the year a risky purchase without seeing it?

I would not see the mileage in itself as a problem: my Shimano equipped bike is on 2134 miles at 6 months old. The battery I use most of the time has done about 1500 of those, and when fully charged now shows 142km estimated range vs 150 when new, in level 1. So I interpret that to mean it is at (142/150) = 94.7% of its original capacity.

If you can get those two numbers for the bike you are looking at, one from the bike's display with a fully charged battery and not ridden since, and the other from the manufacturer's blurb, you can get a rough idea.

A lot depends on how much time if has spent stored and not used, and the state of charge during storage. Ask about all of that!

And establish battery replacement cost. If you had to replace the battery in two years time, does it seem like a good deal still? Can you have a long test ride to establish battery life?

Good luck!

 

[soundwave]

a dealer can do a diagnostic test on the batt and motor if they have the software but will cost 30-50 quid.

i have a 400w batt from 2014 and it is still working but id factor having to buy a new one in to the price as there not cheap

 

[Yak]

Question: generally speaking, on a 36v say, is having the battery as close to 41.6v (that right for fully charged, ‘broken in battery?) one indicator of battery health when buying second hand? I also ‘stalked’ the seller on Strava and checked how far he’d ridden, with how much climbing (he really didn’t like hills). Still no guarantee he hadn’t caned it, left it discharged, or put it in the washing machine. It’s always a gamble.

 

[sjpt]

We bought a 2nd hand Motus (2016 Bosch system) with 1100 miles on the clock in 2018. Battery still going fairly strong at around 4000 miles. It's certainly dropped off a bit (especially in this winter weather) but I'm expecting to get at least another year/1000 miles out of it, hopefully more. I'm sure Soundwave above has been hammering his battery much more than we have ours.

It's really irritating that the battery recharge cycle count isn't one of the things reported on the standard display rather than needing the dealer software. There is more justification that a full discharge test needs a dealer.

 

[sjpt]

Question: generally speaking, on a 36v say, is having the battery as close to 41.6v (that right for fully charged, ‘broken in battery?) one indicator of battery health when buying second hand?

If a battery doesn't charge to around 41.6v it is definitely sick (not necessarily terminally). However, many sick batteries 36v will easily charge to 41.6v and even hold it, but will immediately drop voltage as soon as any current is drawn.

 

[richtea99]

On a more general note, larger wheels will give you a more stable ride because of the additional gyroscopic force they give. The gyroscopic motion acts to keep the bike in line once you're rolling. However, 25" is reasonably large anyway.