I have just fitted a One Up 45t with M8000 cassette and have a slight concern as I have a 17t and a 19t sprocket left over along with 2 Shimano aluminium spacer rings.
The sprockets are as expected but the on line instructions don’t mention the 2 Shimano spacer rings. The instructions tell you to fit One Ups own spacer but do not mention the Shimano spacers.
After a quick pedal up and down the road it all works nicely so I think I have fitted it correctly but would like reassurance from others that have done the conversion. Thanks.

For the morning crowd.

assuming you bought the kit that also comes with an 18t then taking two rings off & adding two from OneUp sort of makes sense to me, not sure about the spaces but I expect that is what you really want to know about.

Be interested in how you find the shifting experience.

What rear mech have you got ?

I have a medium mech & it shifts NOT 100%, but greatly improved with a WOLFTOOTH Goatlink.

show us a pickchur of how it looks now

It should be fairly easy to see whether you’re missing spacers or not. Are the gaps either side of the 18T you’ve installed the same size as the gaps between all the other cogs on the cassette? If not, you might need to install/swap some spacers. If it all looks “right”, it probably is.

I’ve got the oneup 42 tooth expander and am using with the addition of the oneup 18t sprocket.
Shifting, as for MBMc, isn’t 100% but it is bearable in the short term. Basically I can index every gear including the expander, however no matter how hard I try I can’t get the 18t indexed without all of the other gears falling out of line…
Its bearable as all I have to do to get in to 18t is half throw the shifter and it moves up seamlessly. No problems shifting down the block though!
Set up is XT Cassette, SLX shaddow+ long mech with the limit screw wound out as far as it’ll go.

Would be interested in a pic how low does it go? (the mech that is?) is it 26″ safe or 29 only?

Here’s a picture
[/url]20150724_120212[1] by Matt24k, on Flickr[/img]

Pic fail for me

Hopefully pic success now.
I have not used any of the Shimano spacers but have used the single One Up spacer that comes in the kit. The shifting is very slick on the workstand.
The rear mech is an XT M8000 and I have a an Absolute Black 34t Oval on the front.

was meaning in the 45t, what sort of mech/rock clearance do you have?

Here it is on the 45t and this is on a 26inch wheel.
[/url]20150724_123434[1] by Matt24k, on Flickr[/img]

Think 10-42 just got my cash…

Measuring from the lowest part of the mech cage to the outside edge of the rim there is very little difference (less than 5mm) between the 45t and the 40t so I doubt that there will be any clearance gains going 10-42. This assumes the same size front chain ring.
Update: I still have my front 22t granny ring on and the measurement between the lowest part and the edge of the rim is in the same 5mm range.

Just looks really low and very straight, can’t shorten the chain more?

If I take out 2 links it would move the bottom of the hanger to 65mm from the edge of the rim instead of 60mm. For reference I checked a 3×9 bike with 11-34 on the rear and the measurement is 70mm.
I may go up to 36t on the front so 1’ll leave the chain as is for now.
Still haven’t ridden it in anger so will report back.

goat link solved my shifting probs on 42t

This is with 4 rivets out of the chain on the 45t ring. How does that look mech cage wise? It gives 75mm of clearance.
[/url]20150724_143318[1] by Matt24k, on Flickr[/img]

I have to ask but why on earth would anyone need a 45t cassette?

whys your quick release lever on that side?

dirtyrider – Member
whys your quick release lever on that side?

An Ozzie?

A lot of bikes are setup from the shop that way in Oz (or used to be when I lived there).

dirtyrider – Member
whys your quick release lever on that side?

An Ozzie?

A lot of bikes are setup from the shop that way in Oz (or used to be when I lived there)

is that coz water goes the other way down the plug hole down there?

I have to ask but why on earth would anyone need a 45t cassette?

Only way to get the same range as a SRAM cassette with a Shimano one.

Sram is 42t, same as shimano no?

SRAM have a 10t at the other end, Shimano don’t.

Have you cycled the rear suspension to check for chain growth issues?

whys your quick release lever on that side?

Because my front Maxle release is on that side and my workstand usually lives close to the garage wall. I often get accused of being an Aussie, now I know why.

Have you cycled the rear suspension to check for chain growth issues?

Good idea.

I cycled the rear suspension by taking the shock off so I probably got more travel that the shock would allow. There was very little chain growth until the last inch of travel. With that in mind I took 2 rivets out.
[/url]20150725_082231[1] by Matt24k, on Flickr[/img]
I have now ridden about 20 miles on my local loop and the shifting is very positive. I am running a 34t Chain Ring and the rear is 11-45. The idea is to replicate the spread of my 3×9 set up with a bias towards climbing ratios. I have achieved that but with a wider spread between each ratio. So far so good but I need to put some more miles on in various conditions.
Here’s what it looked like with 4 rivets out.
[/url]20150725_081912[1] by Matt24k, on Flickr[/img]

You run 34T?

I personally would’ve got a smaller chainring before messing with the cassette….

You run 34T?

I personally would’ve got a smaller chainring before messing with the cassette….
And lost gears at the other end? Said once in this thread already, and a million times in previous ones. 45T sprocket is about giving extra range, not just giving easier gears at the low end.

For those that aren’t understanding the choice of gearing……..
It is all about trying to replicate the SRAM 10-42 cassette without the using an XD driver and sticking with Shimano mechs.
My previous set up was 3×9 22-32-44 up front and 11-32 on the back.
Yes I do loose some of the taller gears but I wanted to maintain my climbing gears over some taller ones that I may use very occasionally on the road.

For those that aren’t understanding the choice of gearing…..
http://sheldonbrown.com/gears/