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Robestelle
Posts: 1
Joined: Tue May 07, 2024 7:40 pm

by Robestelle

Hi WW
My name is rob


New to this forum but regularly read topics on this so thought I'd join.
50 years old but love to climb hills

My reason is joining is that I am looking to make a very light climbing bike.
My bike to work on is a giant tcr isp rim brake. So decent to start of with.

I fitted 11 speed ultegra di2 a while ago but now with this new project thinking about two things.

1. Should I swap to a 1x to make lighter or just replace the front crankset

And 2. Is the hunt alloy wheel set as good as a light weight carbon set.
Have noticed most carbon sets are about the same weight as the hunt alloy race set.

Cheers rob.
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FishNo6
Posts: 41
Joined: Sun May 08, 2022 10:29 am

by FishNo6

Hi Rob. Welcome to the forum. Nice bike!

I know how to get to a fairly light rim-brake climbing bike. Here we go...

First thing is to establish exactly what you've got and how well it fits you. If you haven't done this already, your first up(side?)-grades should be to optimize your cycling comfort and efficiency. Specifically, that might be saddle length, width, profile, pressure relieving slot and cushioning, handlebar width, reach, tops profile or drops shape - if you're going to bother with drops... It might be gearing, it might be tyre width (and pressure), it might just be bar-tape thickness - if you're going to bother with bar-tape... :) Anything you need to change here obviously goes to the top of your weight-saving priority list.

Find out your TCR's model name, size, year and market. ( A US sold 201x TCR SL probably had some components different from a UK sold 201x TCR SL). From there you can get a headstart on your bike's specific component list. Obviously, you've changed the groupset and I guess the integrated bars are an upgrade too.

There's a handy list of the level of detail to record here : viewtopic.php?f=10&t=121335 Paste that list into a spreadsheet. Identify (specific model name/id and if necessary model year) and record the weights of all your bike's current components. Ideally, you should do this by stripping the bike and individually weighing the components. It will save you time and aggravation in the long term.

If that's currently time or skills prohibitive then research your component weights online, but be aware that manufacturer/reseller weight claims aren't always 100% accurate. In particular, many carbon components - frames, wheels, bars - can have wildly 'optimistic' weight claims - usually only for their smallest size, unpainted, and with all fittings stripped - and a lot of variance from one example to another. Some manufacturers publish their initial target or prototype or version 1 weights but absentmindedly forget to update their websites when they have to strengthen the version 2. On the other hand, published groupset component weights are readily available and usually accurate.

If you've gone the spreadsheet route and recorded manufacturers' weight claims, check the sum of the component weights against your measurement of the actual total bike weight and have a good laugh at the discrepancy. Now strip the bike and individually weigh the components. ;-) Or at least strip back far enough that you can back-calculate the weights accurately. (For example, you don't have to pull your cranks to get to frame weight if you have a rock-solid weight for your model and size cranks, chainrings and bottom bracket).

Now you've established a base-line against which you can compare candidate new components. Spend some time looking at build lists from this forum, concentrating on more recent rim-brake builds. There's a treasure trove of good information, though some of the rim-brake components may no longer be available. Certain components will stand out as obvious opportunities for weight saving.

Establish a budget and your own personal constraints: are you going for all out lightest components, or are you looking for good value cost per gram(me) of weight savings? Also give thought to the importance of durability and safety, bearing in mind your own riding style, terrain and weight. In particular, if this bike is only ever going to be ridden uphill, in the dry, on a good quality road surface, then you can choose lighter components than if it might need to handle sketchy, wet, grip-limited surfaces and the odd high-speed pot-hole impact. Now, as you research and identify potential weight-weenie components, record their weights and costs, and start to prioritize potential purchases based on pennies/cents per gram savings.

I'm guessing that most of us don't start in this fashion - it's much more of a "ooh, shiny Silver eeBrakes G4's", "Super lightweight whooshy carbon wheels", "that Darimo seat-post..." kind of a thing. If this is you - it's definitely me - then go for it, but as your build / rebuild / re-re-build progresses and the inevitable weight-weenie diminishing returns begin to kick in it's going to be well worth prioritising your purchases. And before you fit each new part, remember to weigh and record its actual weight!

Your two specific questions:
1/ 1x? If this bike will be solely dedicated to Hill-Climbs, then Yes. If you also plan to ride the bike to and from the hills and back down them as well, then 1x will suck. Have at it looking at alternatives to the 11-speed Ultegra recall-tastic cranks though. Bad Shimano!
2/ The Hunt alloys. No. They're ok, but they're not great. Historically, and it looks like it's still true, Hunt built its 'Aero' alloy wheels using Kinlin XR-31 rims. Those rims weigh 480g each, at 24mm external they are narrow by modern standards ("optimized for 25/28mm tyres" my arse!). You can easily find lighter, stiffer and wider (if your frame and forks have the clearance) carbon clincher/tubeless rims, but they will cost more than the Hunt alloys. On a budget, look to manufacturers like Light Bicycle. They, and many others, have a range of rim-brake carbon rims (and built up wheels) at different price-points and rider weight limits, which outperform the Hunts. Note that if you're going full weight-weenie then you have to look at tubular rims - but that's outside my experience.

And a few observations that jump out when looking at your bike:
1/ The white paint-job is probably heavy - you won't see many very light white-painted bikes. Unless you're planning to strip the paint then you're probably giving away 100g plus, compared to a predominantly black or plain lacquered carbon frame.
2/ Gatorskins? Keep them if you only Hill Climb on broken glass. :wink: Otherwise, if you're sticking to the tried and true tyre + inner-tube world then look at, for example, Continental GP5000's with some tpu inner tubes for a quick weight savings win. If these will be 'race-day' tyres, save a bit more weight going tubeless with 'time trial' tyres, for example GP5000 TT TR's, at the potential cost of less puncture resistance.
3/ That looks like a heavy old metal-railled saddle. There are lots of lightweight carbon saddles out there - but check that your seat post can handle 7x9mm carbon rails.
4/ I don't know what they are, but the wheels in your picture aren't any Hunt alloys that I can recognise - they're too deep a profile. If they're fully alloy, then they're likely pretty heavy.
5/ The Ultegra dual-pivot brake calipers are great, but eeBrakes G4's are just as great (in my opinion) and a lot lighter. Lighter rim-brakes are available but have mixed reviews as regards braking ability. Don't get counterfeit G4's. Recable with lightweight compressionless outers such as Jagwire Elite Links at the same time.

Good luck with the bike; have fun upgrading and riding it!

raisinberry777
Posts: 350
Joined: Wed Jul 30, 2014 1:09 am

by raisinberry777

Lots of great advice in the post above.

Lightweight always comes with a compromise, whether it's in durability or cost. The saying is 'strong, light, cheap, pick two'.

You save very little weight by going 1x but lose functionality. You will either have to use a larger cassette to get a similar range, or have a significantly reduced range with the same cassette that will either have you compromising by losing climbing gears, or losing gears that you'd use downhill. 1x is best for users in mostly flat territory.

The easiest weight savings here are probably:
- TPU tubes / race tyres (e.g. Continental GP5000)
- Carbon railed saddle (plenty of options for ~20-30 USD on AliExpress)
- Lighter wheels (perhaps some 40mm carbon rims like the Elite Wheels Edge 40 - ~$500 USD and ~1350g - wider, lighter and more aerodynamic than the Hunt aluminium options)
- Lightweight QR axles
- New cranks, considering the 6800 Ultegra ones on there are prone to failure and have been recalled - a good option (if getting a power meter too) is 8-bolt SRAM Red cranks, an XCadey or Sigeyi 4-bolt power meter and put your existing chainrings on those.

As a last point, just from a visual perspective, you should try and find some headset spacers that match the size of your stem/bars. The ones you have now are quite a bit smaller.

As above, a spreadsheet is a great way to understand weight and costs for each component.

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