700 to 650b conversion

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Lyla
Posts: 9
Joined: 8 Dec 2019, 7:47pm

700 to 650b conversion

Post by Lyla »

Hello everyone

I have a 18" frame Voodoo Marasa and would like to swap its 700c tires to 650b ones.

Please do you guys know if it's possible and which tires would you recommend?
I have the feeling that slightly smaller tires would be more appropriate to my height (5'3ft).

Also would like to have chunkier tires, even though, in my limited experience, the current ones 40mm are not that bad.

This is the bike in case someone wants to check geometry etc:

https://www.halfords.com/cycling/bikes/ ... -18-frames

Cheers

L
dim
Posts: 348
Joined: 12 May 2019, 5:59pm

Re: 700 to 650b conversion

Post by dim »

you cannot just change the tyres, you have to change the rims aswell which can be costly (can be done as you have disk brakes)

if the bike is too large for you, changing from 700C to 650b will not make a huge difference .... rather look at a smaller frame (if you bought it new, go back to the shop and tell the manager that you want the smaller 16" frame and that you were sold the wrong size bike) .... assuming that the smaller 16 inch frame fits you and is not too small for you

get the correct size frame then look at tyres that are more comfortable
Lyla
Posts: 9
Joined: 8 Dec 2019, 7:47pm

Re: 700 to 650b conversion

Post by Lyla »

dim wrote:you cannot just change the tyres, you have to change the rims aswell which can be costly (can be done as you have disk brakes)

if the bike is too large for you, changing from 700C to 650b will not make a huge difference .... rather look at a smaller frame (if you bought it new, go back to the shop and tell the manager that you want the smaller 16" frame and that you were sold the wrong size bike) .... assuming that the smaller 16 inch frame fits you and is not too small for you

get the correct size frame then look at tyres that are more comfortable


Thank you for you reply Dim.
The 16" frame was indeed too small for me - I have long arms and legs.

This bike rides well but I also would like to have chunkier tyres.
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gaz
Posts: 14649
Joined: 9 Mar 2007, 12:09pm
Location: Kent

Re: 700 to 650b conversion

Post by gaz »

Lyla wrote:I have the feeling that slightly smaller tires would be more appropriate to my height (5'3ft).

Also would like to have chunkier tires, even though, in my limited experience, the current ones 40mm are not that bad.

650b rims with "chunkier" tyres could well be the same overall diameter as 700c (29") rims with 40mm tyres.
https://www.planetx.co.uk/help/guides/m ... -explained
Lyla
Posts: 9
Joined: 8 Dec 2019, 7:47pm

Re: 700 to 650b conversion

Post by Lyla »

gaz wrote:650b rims with "chunkier" tyres could well be the same overall diameter as 700c (29") rims with 40mm tyres.
https://www.planetx.co.uk/help/guides/m ... -explained


Cheers gaz.
The rim size is 32H so it should accomodate a tyre with more than 2 inches, according to this table:

https://www.lightbicycle.com/newsletter ... e-rim.html

Apparently the bottom bracket height, brake reach and tyre clearance also need to be checked before changing the tyres.
Something for the LBS man!
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: 700 to 650b conversion

Post by Brucey »

32H is usually a drilling, i.e. number of spokes, nothing to do with the width of the rim.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Lyla
Posts: 9
Joined: 8 Dec 2019, 7:47pm

Re: 700 to 650b conversion

Post by Lyla »

Brucey wrote:32H is usually a drilling, i.e. number of spokes, nothing to do with the width of the rim.

cheers


Thanks Brucey
Any idea on where I find this information?
Halfords advisor doesn't have a clue.

I've been speaking to the LBS team and they estimated the total cost in £270
I paid £320 for the bike so it would be a lot of money just to change wheels and tyres.
On the other hand, I don't see any bike with these gears and disc brakes costing less than £700.
Still need to think about it.
LittleGreyCat
Posts: 1177
Joined: 7 Aug 2013, 8:31pm

Re: 700 to 650b conversion

Post by LittleGreyCat »

What is your rim size and how wide a tyre can it take?

If you are lucky the information should be stamped on the rim somewhere.

Otherwise you would have to take the tyre off and measure the width of the rim; I am assuming that the important measurement is the internal distance between the two sides of the rim. That is, the gap into which the tyre fits.

Halfords should know the dimensions of the rim, and the widest tyre that it can comfortably/safely fit.

I suspect you may have decided on an answer to the question "how can I get wider, knobbly tyres?" without fully understanding the basic issues.

One issue nobody has mentioned so far (I think) is clearances within the frame which could limit the width of the tyre that you can fit. As you have disc brakes this is not as much of an issue as with rim brakes.

I assume that you don't have mudguards fitted at the moment because they too can limit the width of tyre you can fit.

Anyway, if you have 700C wheels then you have to fit 700C tyres to match the rims.

If your rims are too narrow then you have to buy new wheels with wider rims. Or you could get the LBS to rebuild the wheels with wider rims.

If you want to change the tyre size from 700C to 650B then as far as I can see that again requires new wheels. Or a wheel rebuild with smaller rims.

In both the above cases you are pricing pre-built wheels off the shelf against a local wheel builder who can re-use the hubs, and perhaps even the spokes if you are just going for a wider rim.

So; what exactly is the problem that you are trying to solve?
slowster
Moderator
Posts: 4629
Joined: 7 Jul 2017, 10:37am

Re: 700 to 650b conversion

Post by slowster »

Lyla wrote:I have the feeling that slightly smaller tires would be more appropriate to my height (5'3ft).

They're not.

Sometimes frames for shorter people are designed specifically for a smaller wheel size, because that avoids compromises in the frame geometry that are likely to cause problems, e.g. toe overlap with the front wheel, an excessively steep seat tube and too long a stretch to reach the handlebars. If you already have a frame which was designed for 700c wheels, then those reasons for using smaller wheels don't apply: you cannot change the geometry of a frame that you already have by changing the wheels. As long as the bike fits you, that is what matters.

Lyla wrote:Also would like to have chunkier tires, even though, in my limited experience, the current ones 40mm are not that bad.


40mm is relatively wide for riding on the road. Chunkier is almost a meaningless/pointless term - it describes the appearance of the tyre, but the superficial appearance does not necessarily bear a close relationship to the quality/performance of the tyre. Just because a tyre looks chunky, that does not necessarily indicate whether it is fast or slow, comfortable or harsh, long lasting or short lived, puncture resistant or puncture prone etc.

Unless you know and can specify more precisely what it is that you are trying to achieve, you are probably going to waste your money.
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: 700 to 650b conversion

Post by Brucey »

Lyla wrote:
Brucey wrote:32H is usually a drilling, i.e. number of spokes, nothing to do with the width of the rim.

cheers


Thanks Brucey
Any idea on where I find this information?


usually the internal rim width is about 3-4mm less than the external rim width.

TBH I am not sure that changing to 650B wheels and tyres will transform your ride in the way you want. It might (if the wheel size comes a bit smaller) allow you to more easily fit wide tyres and mudguards though.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Lyla
Posts: 9
Joined: 8 Dec 2019, 7:47pm

Re: 700 to 650b conversion

Post by Lyla »

slowster wrote:Unless you know and can specify more precisely what it is that you are trying to achieve, you are probably going to waste your money.


Brucey wrote:TBH I am not sure that changing to 650B wheels and tyres will transform your ride in the way you want. It might (if the wheel size comes a bit smaller) allow you to more easily fit wide tyres and mudguards though.

cheers


Thank you slowster and Brucey.
As I said my cycling experience is limited, maybe it's just a matter of getting used to the bike.
My previous one was an old folding Dahon.
I just have the feeling that I the bike is too tall when I'm on the saddle.

During the ride this is not a problem as it is quite stable but when I have to stop I feel I don't have much balance.
Looks ridiculous, I know!

I should give it some more months. Had been using it since September.
Last edited by Lyla on 10 Dec 2019, 10:51am, edited 1 time in total.
Lyla
Posts: 9
Joined: 8 Dec 2019, 7:47pm

Re: 700 to 650b conversion

Post by Lyla »

LittleGreyCat wrote:
I assume that you don't have mudguards fitted at the moment because they too can limit the width of tyre you can fit.

So; what exactly is the problem that you are trying to solve?


Cheers Littlegraycat
I have mudguards and panniers, it was a pain to fit them because the pannier is quite low over the wheel - the Halfords mechanic said it's a result of the frame size.

In the end the clearance was enough to fit both and I have no problems with them - except for the fact that it looks a bit ugly in my opinion.

I will try to add a picture of the bike here.

The problem is the lack of balance that I have sometimes on the bike as I said in the previous post.
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: 700 to 650b conversion

Post by Brucey »

Lyla wrote: As I said my cycling experience is limited, maybe it's just a matter of getting used to the bike.
My previous one was an old folding Dahon.
I just have the feeling that I the bike is too tall when I'm on the saddle.

During the ride this is not a problem as it is quite stable but when I have to stop I feel I don't have much balance.
Looks ridiculous, I know!

I should give it some more months. Had been using it since September.


On most bikes if you are less than about 5'8" if the saddle is set to the correct height for pedalling efficiency then from the saddle it may not be possible to touch the ground with your feet and feel stable. This is exacerbated if you have a MTB-derived bike; these tend to have high bottom brackets. Many are at least an inch higher than (say) a traditional touring bike. So I have a few comments on this

a) if you are riding such a bike then you may need to get used to sliding forwards out of the saddle as you come to a halt, simply so that you can get your feet on the ground. It does take practice to manage this.
b) you are only going to get a reduction of ~19mm in bottom bracket height by changing wheel size from 622 to 584, if you keep the same tyre width. If you increase the tyre width then you could lose all that and maybe more
c) measure up to be sure but it may be worth getting more traditional touring bike simply in order to get a frame that has a lower bottom bracket height.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
zenitb
Posts: 832
Joined: 7 Aug 2018, 9:59pm
Contact:

Cheaper conversion....Decathlon wheels..

Post by zenitb »

Lyla

My wife prefers the wide contact patch and the heavier steering of wider tyres so I think I "get" what you want here...

Decathlon will sell you a pair of 27.5 "Rockrider wheels for £75. You could then swap over your cassette and disks to the new wheels..buy a couple of 27.5 tyres and inner tubes for £40 and you are good to go. Not sure what the bike shop was planning to do..maybe build custom wheels? My cheaper suggestion assumes you are handy with some basic tools but you could always get the bods at Decathlon to do the swap assuming you have a store close..

Here is the rockrider front wheel..

https://www.decathlon.co.uk/275-mountai ... 51216.html

..and rear

https://www.decathlon.co.uk/275-mountai ... 51215.html

I have used the 26" version of the "Rockrider" wheel in a crisis with my tandem and its been fine - its still on the tandem in fact. One thing I would say though is the bearings were very tight from the store. I got my cone spanners out and got them "just right" not something you would necessarily need to do though.

I strongly recommend the Schwalbe Land Cruiser or wider Marathon tyres ,available in 27.5 - quality rubber, v.puncture resistant and a chunky 2" wide..what you want if I have read you right.

All this assumes a bit of bike knowledge and a few bike tools. It does have the advantage that you could easily swap beween the wheels though..and its way cheaper.

See what you think....
Last edited by zenitb on 10 Dec 2019, 1:18pm, edited 4 times in total.
mattsccm
Posts: 5101
Joined: 28 Nov 2009, 9:44pm

Re: 700 to 650b conversion

Post by mattsccm »

Just a thought. Maybe someone, (Brucey???) could simplify all theses posts into one simple paragraph. It is clear that the OP isn't sure about things and it is actually a very simple issue. To many of us its just a wheel swap.
The why's are another issue. Another short paragraph maybe.
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