Planet X RT-58 Alloy sizing advice

Mertyn

Hello,

Quick question on the RT-58 alloy sizing. I know trying out the bike is ideal but I live down south so it'll have to be an online purchase

http://www.planetx.co.uk/i/q/EBPX58TI/planet-x-rt-58-v2-alloy-shimano-tiagra-road-bike

My measurements:
Actual Inseam 86 Cm (34")
Sternal Notch 152 Cm
Total Height 182 Cm (6'0")

Now, based on Planet X's size guide they would have me on the XL (5'10"-6'2") however I'd pretty surprised that at 6 foot i'd be on their largest bike, i'm not exactly a giant! The XL also has a 59cm ETT and 11cm stem.

Calculators based on above measurements suggest I would need approx. a 56cm ETT which would put me between the Medium and Large frame sizes however Planet X suggests these bikes would be suitable for people between 5'5"-5'10" which is putting me off.

Does anyone have one of these bikes on any advice on the correct size for me based on the above?

Cheers

diamonddog

I am 5'5'' and no way would I be riding the size suggested on the PX site (med), I would be on the XS frame which is the size of my PX and Canyon bikes. The Canyon is exactly the same tt length as the XS RT 58 at 525mm and my PX tt length is 530mm.

dj58

Strange sizing on those frames, I think the XL 55cm will be too big a stretch, the 53cm may even be too long, depending on your reach. If you are between sizes 51cm and 53cm, the usual advice is to go for the smaller frame and use a longer stem/seatpost, unless you prefer the extra height of the longer head tube on the bigger frame, were you may also need to use a shorter stem length.

If I were you I would note down the dimension of the 51cm and 53cm bikes and go to a local shop and go and sit on the equivalent size endurance geometry bikes to get an idea of what fits. You can also ring PX and ask them what they suggest and if you get it wrong ask if you can return, unused and swop for another size.

Mertyn

Thanks, that's what I was thinking. It looks like it has quite a short seat tube so i'd expect to be showing a lot of the seat post? Perhaps large is the way forward - decisions!

dj58

Having more seatpost showing isn't necessarily a bad thing, once set correctly for your leg length, it is the reach to and height of the bars that determine your comfort on the bike.

adlopa

Anywhere near St Albans? I bought my carbon RT-58 through Triathlon Zone, after a quick measure (not a fitting) in-store to check sizing. https://www.localstore.co.uk/store/5136 ... st-albans/

Mertyn

Unfortunately not, I'm based in Hampshire just off the M3.

Do the carbon rt-58's have the same geometry? What size are you riding and what are your measurements if you don't mind saying?

General consensus is that the size guides on Planet X are wrong, I think I need to get in touch with them and see if they have some more knowledge.

diamonddog

It is not unusual for the web site to be wrong on many things. I agree with DJ58 re the frame sizing for you, I think you would feel really stretched on the one that is recommended on the web site.

Mertyn

Agreed, thanks for your help. I've just had a response from Planet X and based on height and inseam they have recommended a large so even they don't agree with their own website!

diamonddog

Par for the course but they are good bikes IME.

d00d4h

Mertyn wrote:

Unfortunately not, I'm based in Hampshire just off the M3.

Do the carbon rt-58's have the same geometry? What size are you riding and what are your measurements if you don't mind saying?

General consensus is that the size guides on Planet X are wrong, I think I need to get in touch with them and see if they have some more knowledge.

The carbon ones have different geometry. I'm 5'11" and have a carbon one in 56cm.
According to the website, I'd be on an XL (55cm) alloy one

timothyw

Assuming that you have a bike that fits you already, the things to compare are the stack and reach measurements, which give you the position of the top of the head tube relative to the bottom bracket.

Saddle position is usually fairly easy to dial in as desired, the tricky part is handlebar position.

peterrsv2

I,m 6'2 and have just built up a size large RT58 alloy for a winter bike fits me perfectly

jgsi

I also 6 2 and have a Medium Alloy RT58 which fits me perfectly.

Mertyn

Thanks guys, i've ordered the large size, should be coming in the next few days.

My only current bike is a Brompton which I don't think will be much help

adlopa

Mertyn wrote:

Do the carbon rt-58's have the same geometry? What size are you riding and what are your measurements if you don't mind saying?

I can't see why the geometries would change between frame material, but I don't know how the sizes compare. That said, my Large has a 570mm effective top tube length, which matches that on the L/53 alloy frame, so perhaps the two are the same.

Mine fits me (5' 11" and 32" inside leg) perfectly. I did consider the Medium, but wanted to avoid too much toe overlap. I have no reach problems with a 100mm stem.

d00d4h

It looks like the geometry has changed for the V2 alloy.

This is the original version:

https://web-beta.archive.org/web/20150224224218/http://www.planetx.co.uk:80/i/q/CBPXRT58ALUTIA/planet-x-rt-58-alloy-shimano-tiagra-road-bike

The carbon bike is the same.

It looks like the V2 is a different bike, which makes sense, as it now has greater clearance for wider tyres.

Mertyn

Bike has arrived and it's lovely, I put it together and gave it a brief spin this morning (getting used to clipless pedals is fun :shock: )

I have a question on the gears, currently the tiagra groupset is sounding, shall we say... agricultural. There are clicks and bumps galore. It's changing gears smoothly but I am feeling some slight knocks when pedaling and even when winding backwards by hand.

Is this just a case of new bike wearing in or is it likely i'll need to tinker? I'm fairly handy having replaced my brommies rear sprockets etc so I doubt it's beyond me but i'm not sure what good looks/feels like so any advice would be appreciated.

Appreciate all your advice.

diamonddog

Clicks could be a stiff link on the chain. The low end Shimano groupset on my turbo bike has always been a lot noisier than the other higher end groupsets I use, having said that it changes perfectly with very little attention and there are no clicks or bumps.

Mertyn

It actually looks like the chain might be stiff, when I spin the chain slowly I can see the noise is the chain sticking slightly when it moves from the top jockey wheel to the cassette. Is this something that'll resolve itself with use or should I add a bit of chain lube?

diamonddog

Try giving the link a wiggle around using a slight twisting action, this worked for me on one of my bikes that only clicked in one gear. Give it a Google loads of info out there.

rachidH

Hi Mertyn,

Quick question relative to the sizing of your RT-58, as I'm approximately the same height as you (183cm total height and 87 inseam), and I was also hesitating between the L and the XL sizes of the RT-58.

Are you happy with your L? Would you recommend it sizewise?

Cheers!

Mertyn

Hello,

I definitely wouldn't go for the XL, the L seems to be a really good fit for me.

Sorry for the delay in getting back to you!

deadlegs

Sorry bit late as Mertyn has already purchased but might help someone else:
I recently got Size M in Planet X RT-58 aluminium frame. I had proper bike fit first before buying 2 bikes online. PX size guide says I should be XL. I'm 5'11 with 32" inseam. PX says M is for 5'5 max height! I called my bike fitter (Simon at Cadence Cycling) who checked and said PX sizing was well out for their top tube lengths.

Bought the M and it fits perfectly. Lot of seat post showing but well within max limit. Also bought M Canyon Ultimate - which fits great.

fpinela8

Very good price at the moment (rt-58 v2 tiagra - £439 using 20% discount). Considering this as a Commuter/Winter bike but I'm worried about the tyre clearance.

Does anyone know if with full mudguards on I can use 25c tyres?

deadlegs

I'm using Crud roadracer Mk 3 mudguards on my PX RT-58. Conti GP 4000 II S tyres in 25mm. It's tight and took a bit of fiddling to set up but just enough clearance.

fpinela8

If those are tight it would be very difficult to squeeze in full mudguards with 25mm!

Emailed PX and they recommend 23mm tyres max with full mudguards, which is not good for what I would like. :roll: