My more major project to lighten an R8000 disc brake road bike

daniel_b

Picked up a Scott addict RC30 at the weekend, yet to weigh it though.

Historically I have used Garmin Vector 2 pedals, but am going to look to use a 4iiii R8000 crank (£255) IF it will fit - have printed the guide that should reveal whether it will, and will sort that this week.
If it fits, then I'm going to look to fit some of these pedals which I can acquire for £210:
https://www.probikekit.co.uk/bicycle-pedals-cleats/look-keo-blade-carbon-ceramic-bearing-ti-pedals/12315281.html


Once I know what size stem I need, will order a Creston IC SL setup to replace the separates on there now, that should save a fair bit of weight.

The wheels aren't bad, but they are not light, something around 1720g, plus the tyres and tubes are heavy.
In communucation with Spokesman wheels about some super light clinchers, probably 30mm deep and either Tune or Extralite hubs, and would pair those with latex tubes and either 25 or 28mm GP5000s.

Stock saddle will be swapped out for the Berk currently on my CR1 SL.

Will try and remember to update this post as weights come in, and changes are made :-)

I'm going to weigh the bike as it is, plus the weight of a pair of Vector 2s, and then I'll use that as the reference original weight, and see how far down I can get it whilst sticking to the R8000 groupset -I'm hoping (Possibly optimistically) for low 7, sub 7 would be mighty, but I highly doubt that would be possible without a wholesale groupset change.

MattFalle

Interesting project dude - keep us updated.

daniel_b

Oh and if anyone knows of any lightweight bolts etc I could be looking to replace to shave a few more grams, would be keen to hear.

Won't want to tinker with the seatpost bolt, or anything around the stem/handlebars, but there may be other bolts that I could be looking at to replace, as long as they are as strong or stronger than the originals - presuming the new wheels will come with decently light through axles anyway.

MattFalle

Just go on Ebay and look for titanium bolts - let me dig out the name for the guys i use.

why won't you change seat clamp bolt? no understand? stem bolts the same? top end stems use ti bolts anyway.

MattFalle

RaceTi up in Leeds.

or Pro Bolt.

daniel_b

MattFalle said:

Just go on Ebay and look for titanium bolts - let me dig out the name for the guys i use.

why won't you change seat clamp bolt? no understand? stem bolts the same? top end stems use ti bolts anyway.

Only because it's a proprietary seat clamp, and is pretty super light anyway - I can foresee warranty challenges if I changed it and had an issue, but we'll see, food for thought for sure - thanks for those names above.

I could look at the ones that bolt the callipers to the frame.

ibr17xvii

Regarding the 4iiii PM - I printed off the guide you get from their website that's supposed to show how much room you have for the sensor between that & the chainstay on my TCR.

The guide showed it really quite tight (probably within a couple of mm) but when I got the crank itself there was loads of room.

YMMV of course.

daniel_b

ibr17xvii said:

Regarding the 4iiii PM - I printed off the guide you get from their website that's supposed to show how much room you have for the sensor between that & the chainstay on my TCR.

The guide showed it really quite tight (probably within a couple of mm) but when I got the crank itself there was loads of room.

YMMV of course.

LOL, that's good to know! Do you happen to have a pic (Or a measurement for where it starts) of your crank arm so I can see where abouts it lurks, and can then compare with the existing crank.

I saw an AAA battery mentioned as a valid measuring device - sounds like they maybe want a LOT of leeway to be extra safe.
Perhaps a really powerful rider (not me) could bend/twist the cranks........?

Is it the 2.0 you have, that seems to be the current one, though can't imagine they have changed size wise much if at all.

ibr17xvii

Will be really interesting to see how much you can get the weight down.

Without opening the whole disc v rim thing (again), for me the major downside of discs is the weight.

Depending on how far you want to take it obviously, to get a seriously light disc bike you have to spend a serious amount of cash, probably not far from pro level which for the average rider is simply unattainable.

Good luck though!

MattFalle

daniel_b said:

MattFalle said:

Just go on Ebay and look for titanium bolts - let me dig out the name for the guys i use.

why won't you change seat clamp bolt? no understand? stem bolts the same? top end stems use ti bolts anyway.

Only because it's a proprietary seat clamp, and is pretty super light anyway - I can foresee warranty challenges if I changed it and had an issue, but we'll see, food for thought for sure - thanks for those names above.

I could look at the ones that bolt the callipers to the frame.

got ya completely dude - groovy banananarama sauce.

remind me again - electronic or mechanical?

MattFalle

daniel_b said:

MattFalle said:

Just go on Ebay and look for titanium bolts - let me dig out the name for the guys i use.

why won't you change seat clamp bolt? no understand? stem bolts the same? top end stems use ti bolts anyway.

Only because it's a proprietary seat clamp, and is pretty super light anyway - I can foresee warranty challenges if I changed it and had an issue, but we'll see, food for thought for sure - thanks for those names above.

I could look at the ones that bolt the callipers to the frame.

Ali 'cage bolts from Wiggle cost nothing and weigh nothing if you need some.

MattFalle

Are you going clincher/tubular/tubeless?

ibr17xvii

daniel_b said:

ibr17xvii said:

Regarding the 4iiii PM - I printed off the guide you get from their website that's supposed to show how much room you have for the sensor between that & the chainstay on my TCR.

The guide showed it really quite tight (probably within a couple of mm) but when I got the crank itself there was loads of room.

YMMV of course.

LOL, that's good to know! Do you happen to have a pic (Or a measurement for where it starts) of your crank arm so I can see where abouts it lurks, and can then compare with the existing crank.

I saw an AAA battery mentioned as a valid measuring device - sounds like they maybe want a LOT of leeway to be extra safe.
Perhaps a really powerful rider (not me) could bend/twist the cranks........?

Is it the 2.0 you have, that seems to be the current one, though can't imagine they have changed size wise much if at all.

I saw the "battery" test as well which didn't work at all for me either & if I'd have believed that I wouldn't have ended up buying one.

Should be able to get you a pic / measurement later.

daniel_b

MattFalle said:

Are you going clincher/tubular/tubeless?

Plan was to go clincher with latex tubes and GP5000s, like that setup a lot on both my Foil and the CR1, don't really want sealant spraying all over me and my frame.

Spokesman have some back to say that the lighter rim is recommended for 30mm or greater width tyres, think it's a 22mm internal width, where as the heavier 18mm internal width is more for 25/28mm.

The Tune hubs add on £366, but shave off 92g, the Extralites are a whopping £660 extra, but take off nearly 200g.

He's recommended a set with Hope RS4 hubs weighing 1395g, but I think I fancy something a bit more exotic.

I wouldn't voluntarily go out on this bike in the rain, or if there was a strong chance of rain, so I think the seals are not the most important part of the wheel, as he alluded to the Tune and Extralite seals not being particularly hardy, and also suggested they may need more regular servicing.
I can't see mileage being HUGE though.

MattFalle

You don't fancy tubs?

MattFalle

Howevet, if your preferred tyre/tube combo is lighter/same and you're more confident with that set up then may as well go for it.

mrb123

Shimano XTR rotors are supposed to be lighter than Dura Ace ones.

daniel_b

mrb123 said:

Shimano XTR rotors are supposed to be lighter than Dura Ace ones.

Cheers Mrb, yep I had spotted that (But forgotten to add to the shopping list), seems it was a standard upgrade previous years, where as now they only make the XTR rotor anyway!

This one I think?
https://tredz.co.uk/.Shimano-RT-MT900-XTR-Disc-Rotor_205730.htm




160s front and rear it seems.

Does anyone know what the difference is between Black/Silver or Silver/Black?
I can seemingly only find one picture, and it's the one above, but I see those as options on various sites.

MattFalle

Fibrelyte carbon chainrings - 1/2 the weight of normal ones

MattFalle

https://www.fibre-lyte.co.uk/fl/fl_cycles_carbon_chainring.html

daniel_b

MattFalle said:

https://www.fibre-lyte.co.uk/fl/fl_cycles_carbon_chainring.html

Thankyou - prices are high, but not horrific, hadn't overly considered that until now.

MattFalle

Considering you're looking at minimal mileage be silly not to...

1x for a chunk of weight saving? Go for a Red cassette and save a huge chunk of weight as well....

N0bodyOfTheGoat

Google suggests the cs-r7000 11-30 cassette is ~304g, the cs-r9001 11-25 is ~175g and only £200 from Merlin!

darkhairedlord

Drill through the centres of all the bolts.
Just have bar-tape where your hands touch.
Only put half of the hydraulic fluid in the reservoirs.
Remove two links from the chain.
Drill the rotors.
Buy a 38cm bar and chop 2cm off the ends of the drops.
Drill the bar end plugs.
Fit narrower hydraulic lines (less fluid, less weight).

MattFalle

Sand all the paint off and have bare lacquer - saved 150g on the Madone over lockdown

Superlight chain from Taiwan - PCY or something - let me check.

Gutted out Record carbon 'lever on the left - 1x but save a shedload by having no internals

Zipps and really nice light tubs

Chucked on some EC90SLX forks

came in at 5.98 or something silly and all perfect for the road.

Are your forks carbon or ali steerer? carbon steerer will save loads

MattFalle

stupid light Miche cassette, stupid light chain, Zipps

MattFalle

It also had rubbish Ultegra 8000 groupset on it, so if it had Red would have been mega weight saving.

super_davo

I can't help thinking you're trying to make an apple out of an orange.

If you want super lightweight then you should go rim brake. If you want all weather stopping ability then you should go disc.

If you're making component choices that mean you can't / don't want to ride the bike in the rain e.g. superlight hubs with poor sealing you lose the major advantage of the disc brakes but you still have the extra weight to lug around the rest of the time.

If I were you I would pick off the low hanging fruit like ti bolts, rotors and wheels but accept you've got the wrong groupset and frame design to get very far under 8kg.

daniel_b

99% sure the forks are carbon steerer - they were on my CR1 SL and that's 9 years old, and also HMX carbon, so can't imagine they would have gone backwards in that time.

N0bodyOfTheGoat said:

Google suggests the cs-r7000 11-30 cassette is ~304g, the cs-r9001 11-25 is ~175g and only £200 from Merlin!

I hadn't overly noted the cassette was not Ultegra - bit odd.
I sold the DA one from my Foil as read so many bad things about them, and put an R8000 on there instead.
As luck would have it, I have R8000 11-30 and 11-32 in stock, so will likely put the one it comes with onto the CR1 (As that has an 11-28 on it) and put one of the stock items onto the new wheels, the 11-32 would probably make more sense, but hardly saves any weight at about 292g according to Wiggle.
The 11-30 is 269g, I suspect the 11-30 would do to be fair, but wanted to set it up so I can take it with confidence into the Alps, Dolomites and Pyrenees etc.

ibr17xvii

Pic of my 4iiii PM - excuse the towel underneath! The bike is on the turbo & the matt I use is black so the crank / sensor wouldn't show up very well.

FYI from the edge of the PM sensor to the end of my crank at the pedal (175mm) is approx 9cm.

darkhairedlord