Buying new MTB wheels - correct sizing advice?

colinmc400
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Buying new MTB wheels - correct sizing advice?

Postby colinmc400 » Wed Sep 17, 2014 4:53 pm

Guys, i need to replace my rear OEM Giant wheel on my MTB, as the rim is toast. How exactly do you need to size the wheels to get the right thing? I see various terms i have no idea about, compared to my normal road wheels. It looks like there are different size axles, perhaps different disc mounting etc(centrelock eh??). This is typical of what gets advertised and i have no idea what i have fitted. I can read the tyre size of mine, but not sure baout the rest.i can pull the axles and measure them i spose.

Shimano MT55 29er Centre-Lock Rear Disc Wheel
Shimano MTB wheels are designed and engineered to the guiding principles of the Shimano quality legacy in every aspect. Optimized for confident, reliable all day trail rides.
Shimano MT55 29er Wheel Features
• Weld joint rim gives enough strength.
• High quality sealing Cup & Cone bearing.
• Quick pawl engagement for perfect traction.
• CENTER LOCK rotor mount for easy and quick installation.
• 29ER version (WH-MT55-29).
• Weight: 1100g (WH-MT55-R-29).
Shimano MT55 29er Wheel Specifications
• Brake Type: Disc
• Axle Type:QR
• Freehub Body: 8/9/10 speed
• Over Locknut:100.0
• Contact Sealing: Yes
• Rim Type: Clincher
• Rim Size: 29"
• Rim Height19.0
• Rim Width24.6
• Spoke: Butted (2.0)/Round
• Recommended Tyre: 1.50-2.25

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Duck!
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Re: Buying new MTB wheels - correct sizing advice?

Postby Duck! » Wed Sep 17, 2014 6:11 pm

There are three different wheel diameters used in MTBs, 26", 27.5" (also called 650B) and 29". Your tyre size will tell you what you have if you don't already know.

Axles: there are regular quick release types the same as what your familiar with on your road bike, often labelled as 100 x 9 for front and 135 x 10 for rear; and there are "through axles", which you need to completely remove in order to drop the wheel out 'cos the frame & fork don't have regular open dropouts. Front through-axles are 15mm (20mm on heavy-duty downhill bikes), rear are 12mm x 142.

Brake disc mounts: there are only two types, Internationa Standard (IS) 6-bolt, and Shimano's proprietary Centrelock. Your OEM wheels will be 6-bolt. There are adaptors that allow you to fit your 6-bolt rotors to Centrelock hubs, but Centrelock rotors can't be made to fit 6-bolt hubs.
I had a thought, but it got run over as it crossed my mind.

colinmc400
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Re: Buying new MTB wheels - correct sizing advice?

Postby colinmc400 » Thu Sep 18, 2014 9:41 am

Thanks for that Duck, that helps explain some stuff then. Looks like i best avoid Shimano wheels with a centrelock then. So spcing wise, to ensure the brake disc is correctly aligned with the brake caliper, are all wheels the same?

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Re: Buying new MTB wheels - correct sizing advice?

Postby silentbutdeadly » Thu Sep 18, 2014 11:42 am

colinmc400 wrote:So spacing wise, to ensure the brake disc is correctly aligned with the brake caliper, are all wheels the same?
Broadly...yes. As Duck says you could have a 135mm or 142mm spacing at the rear...this is the primary measure. After that there's a couple of axle options. Easiest thing is to either show us a picture or tell us the model, year and wheel diameter of your Giant and we can help you out.

I should point out that Shimano MT55 are hardly likely to be an improvement on the wheel you are seeking to replace...
Ours is not to reason why...merely to point and giggle

colinmc400
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Re: Buying new MTB wheels - correct sizing advice?

Postby colinmc400 » Fri Sep 19, 2014 2:09 pm

I'll pull the wheels off at the weekend and check tyre sizes and axle dimensions, then see where that leads me. SBD, you'd be surprised how rubbish the OEM Giants are and how heavy and i fancy 2 Flintstones car wheels, made from rock would be an upgrade!!

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silentbutdeadly
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Re: Buying new MTB wheels - correct sizing advice?

Postby silentbutdeadly » Fri Sep 19, 2014 9:43 pm

No I wouldn't. I have the remains of a set of PCX-2 wheels hanging on the shed wall...
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colinmc400
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Re: Buying new MTB wheels - correct sizing advice?

Postby colinmc400 » Sun Sep 21, 2014 3:03 pm

Righto, had the wheels off and it looks like they are more hyrbid orientated and a bid odd size. The front tyre is 700 x 35 and the rear 700 x 32. They are both Giant P-RX2 if that helps. They appear to have std quick release skewers on both ends, with the front having a space between the inside of the forks of @100mm and the rear @138mm. Both skewers are @5mm diameter. Both discs are Shimano and have 160mm diameter printed on them and are a 6 bolt fixing arrangement to the hub. The rims seem to have 622-19 printed on them, if that is the rim width maybe??

So does this narrow it down as to what i could buy? Its a $1200 bike, so don't wanna spend a fortune(save that for the Spesh S Works Tarmac frame i just bought and the $0000's that will get spent on that). Prolly willing to spend $500 for the pair of new wheels.

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Re: Buying new MTB wheels - correct sizing advice?

Postby Baalzamon » Sun Sep 21, 2014 4:12 pm

700 in MTB terms is 29er
Masi Speciale CX 2008 - Brooks B17 special saddle, Garmin Edge 810
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Re: Buying new MTB wheels - correct sizing advice?

Postby trailgumby » Sun Sep 21, 2014 9:04 pm

Get some Hopes Hoops from c r c. Stan's Arch EX29er rims laced to Hope hubs front and rear.

They will outlast several bikes, and the hubs front and rear can be adapted to different axle standards (eg 15mm thru-axle on the front and 142x12 on the rear) just by swapping inserts on the hub ends.

I have Stans rims on my 29er and they are super easy to work with for tubeless. This is perhaps a little more than you were initially planning on spending, but these wheels will be a longer term investment than your current ride.

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silentbutdeadly
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Re: Buying new MTB wheels - correct sizing advice?

Postby silentbutdeadly » Tue Sep 23, 2014 3:05 pm

colinmc400 wrote:Righto, had the wheels off and it looks like they are more hyrbid orientated and a bid odd size. The front tyre is 700 x 35 and the rear 700 x 32. They are both Giant P-RX2 if that helps. They appear to have std quick release skewers on both ends, with the front having a space between the inside of the forks of @100mm and the rear @138mm. Both skewers are @5mm diameter. Both discs are Shimano and have 160mm diameter printed on them and are a 6 bolt fixing arrangement to the hub. The rims seem to have 622-19 printed on them, if that is the rim width maybe??

So does this narrow it down as to what i could buy? Its a $1200 bike, so don't wanna spend a fortune(save that for the Spesh S Works Tarmac frame i just bought and the $0000's that will get spent on that). Prolly willing to spend $500 for the pair of new wheels.
Basically you can get any 29er or 700C 6 bolt disc wheelset that has a 9mm QR at the front and same at the rear (but with a 135 mm rear axle width).

These will work http://www.bikebug.com/wheels-parts-mtb ... 27517.html" onclick="window.open(this.href);return false; they aren't as good as Hope Hoop but they are cheaper. TBSM has SRAM Rise 40 wheels that'll suit for about $450 a pair
Ours is not to reason why...merely to point and giggle

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Re: Buying new MTB wheels - correct sizing advice?

Postby Duck! » Tue Sep 23, 2014 5:16 pm

silentbutdeadly wrote:
colinmc400 wrote:Righto, had the wheels off and it looks like they are more hyrbid orientated and a bid odd size. The front tyre is 700 x 35 and the rear 700 x 32. They are both Giant P-RX2 if that helps. They appear to have std quick release skewers on both ends, with the front having a space between the inside of the forks of @100mm and the rear @138mm. Both skewers are @5mm diameter. Both discs are Shimano and have 160mm diameter printed on them and are a 6 bolt fixing arrangement to the hub. The rims seem to have 622-19 printed on them, if that is the rim width maybe??

So does this narrow it down as to what i could buy? Its a $1200 bike, so don't wanna spend a fortune(save that for the Spesh S Works Tarmac frame i just bought and the $0000's that will get spent on that). Prolly willing to spend $500 for the pair of new wheels.
Basically you can get any 29er or 700C 6 bolt disc wheelset that has a 9mm QR at the front and same at the rear (but with a 135 mm rear axle width).
Except rear Q/R axles are 10mm diameter. :wink:
I had a thought, but it got run over as it crossed my mind.

colinmc400
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Re: Buying new MTB wheels - correct sizing advice?

Postby colinmc400 » Wed Sep 24, 2014 9:59 am

Duck! wrote:[
Basically you can get any 29er or 700C 6 bolt disc wheelset that has a 9mm QR at the front and same at the rear (but with a 135 mm rear axle width).
Except rear Q/R axles are 10mm diameter. :wink:[/quote]

So the 10mm axle dimension is measured where exactly, as i measured mine and i could have sworn they were @5mm??? That was right in the middle of the axle shaft, as opposed to the hole size in the fork or on the chain stay.

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Re: Buying new MTB wheels - correct sizing advice?

Postby Duck! » Wed Sep 24, 2014 10:17 am

Axle diameter is measured at the section which sits in the dropouts. The 5mm measurement you've got would be the Q/R skewers, not the axles. For further reference, axle length is measured from the outer faces of the locknuts on the axle, not from the actual axle ends (there's about 5mm each end past the locknuts to sit in the dropouts).
I had a thought, but it got run over as it crossed my mind.

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Re: Buying new MTB wheels - correct sizing advice?

Postby silentbutdeadly » Wed Sep 24, 2014 10:44 am

Duck! wrote:Except rear Q/R axles are 10mm diameter. :wink:
:lol: Pedant! :P
Ours is not to reason why...merely to point and giggle

colinmc400
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Re: Buying new MTB wheels - correct sizing advice?

Postby colinmc400 » Wed Sep 24, 2014 2:44 pm

Duck! wrote:Axle diameter is measured at the section which sits in the dropouts. The 5mm measurement you've got would be the Q/R skewers, not the axles. For further reference, axle length is measured from the outer faces of the locknuts on the axle, not from the actual axle ends (there's about 5mm each end past the locknuts to sit in the dropouts).
Phew, thats explained that then! Cheers.

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Re: Buying new MTB wheels - correct sizing advice?

Postby colinmc400 » Wed Sep 24, 2014 2:50 pm

Well these would seem to fit the bill. The XC would seem to be a bit lighter and as this is a "soft roader" only, would seem to suit.

http://www.this link is broken/au/e ... prod124948" onclick="window.open(this.href);return false;
http://www.this link is broken/au/e ... prod124946" onclick="window.open(this.href);return false;

Or are these better?

http://www.this link is broken/au/e ... prod114423" onclick="window.open(this.href);return false;

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silentbutdeadly
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Re: Buying new MTB wheels - correct sizing advice?

Postby silentbutdeadly » Thu Sep 25, 2014 10:55 am

Those Hope Tech XC wheels are a bargain with the 10% off Hope at the moment. Under $500 shipped with the front hub adapters included is a win...
Ours is not to reason why...merely to point and giggle

colinmc400
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Re: Buying new MTB wheels - correct sizing advice?

Postby colinmc400 » Thu Sep 25, 2014 3:30 pm

I reckon a pair of those Hope's it is then, as i have a Chain Reaction voucher here as well and it makes it cheaper again - cheers!

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