Lightcarbon: LCR018-D (endurance all-road)

[Westman]

Ok thanks,
- 184cm
- Inseam: approximately 85–86 cm
- Wingspan: 194 cm
I think the 560 will be more comfortable, even though they recommended the 540 to me.

[Nikh]

I'm 183cm, just 82cm inseam and have chosen 520. I use it as a roadbike andcweren't sure about 52 or 54.
So I tried a few bikes before. Specialized SL8 in 54 was my favorite, but too low. LCR018-D in 52mm is 15mm higher (7mm+8mm risebar)
I would've been able to get in my position on both bikes. But on size LCR 54 I wouldn't have any spacer left and i would have chosen a shorter stemlength.

Blue SL8
Red 52
Yellow 54

[Westman]

I'm really sorry to spam but I'm totally lost...
Ratio after hours talking with LLMs:
540 : 55 %
560 : 45 %
LightCarbon's engineer has consistently recommended the 54 and not recommended the 56 after several emails. Even after I provided additional information about my current bike fit, body measurements and riding goals, they still recommend:
Size 54
15 mm offset seatpost
HBR17 integrated cockpit with a 110 mm stem
10 mm of headset spacers
I'm hesitating because of their recommended setup for the size 54 already seems to push the frame toward the upper end of its adjustment range. That makes me wonder whether I'm already close to the upper limit of the 54, and whether the 56 might offer a more natural fit with fewer compensating adjustments.

My current bike is a Triban RC500 size L, which fits me well. I ride with:
110 mm stem
No spacers
Saddle height: ~765 mm
Saddle setback: ~120 mm
Saddle to handlebar distance: ~580 mm
Saddle to hood distance: ~650 mm
Saddle-to-handlebar drop: ~95 mm

My priority is comfort on long rides, not an aggressive race position. I also plan to keep this bike for many years.
My concern is that the 54 seems to require a relatively long stem (110 mm) and spacers to achieve my position, while the 56 appears closer to my current bike's overall fit. On the other hand, I don't want to end up with a frame that's too large.

My body measurements are:
Height: 184 cm
Inseam: 86 cm
Wingspan: 194 cm (+10 cm compared to my height)
Torso length (sternum to inseam): ~68.2 cm
Arm length (acromion to tip of middle finger): ~84 cm
Femur length: ~46 cm

I'm worried that the handlebar might be too low on the size 54
Based on these measurements and my current position, would you choose the 54 or the 56, and why?

[Abreu.T]

https://geometrygeeks.bike/compare/triban-rc500-2019-l,lightcarbon-lcr018-d-2025-54,lightcarbon-lcr018-d-2025-56/


You buy the bike you want,

After compare geometrys LCR018 in 56 is more near your atual bike, if you feel good position wise on the Triban my opinion  is "i would go for a 56".

For me was the opposite, i was on a bigger frame 56 (3t Strada ) and i felt too stretch needed to have the sadle too far foward etc... , so i went with 54.

 

[Schneedolf]

I think you just want to hear a specific answer which you already have given yourself between the lines.

[Abreu.T]

Just finished my first build and my first ride of 85 km.

Frame: Lightcarbon LCR018-D 56 cm
Groupset: Shimano 105 Di2 52/36 11-36T 165mm
Wheel set: Elitewheels Edge 3.0 52mm
Saddle: Ryet 3D Carbon
Seat Post with zero setback

8,1 kg (with with pedals, computer mount, bottle cage, handlebar tape)


Unfortunately, the saddle is still causing problems. The seatpost stays in place after I greased the sliding surfaces of the clamp and the bolt, but the saddle tilts under load.
I’ve already tightened the clamp quite firmly, but I was careful because of the carbon struts (recommended torque: max. 5 Nm). Even so, the saddle tipped over when I hit a pothole. I haven’t used carbon paste yet.
What would you recommend I do next?

• Tighten the bolts even more? (Unfortunately, a torque wrench won’t fit due to the design.)
• Try carbon paste?

Do you have any tips?

Had the same problem, after confirmation with LC (whatsapp message from wendy dat Engineer Team says i can torque to 10NM), i had more carbon paste and now torque to 9/10NM, fixed the problem .

[Westman]

I think you just want to hear a specific answer which you already have given yourself between the lines.

Surely, but I'm not confident and stubborn enough to make a decision based solely on that. That's why I'm asking here ToT. LLMs discussions didn't told me I was wrong. If that had been the case, I would have changed my mind and gone with a 54.

[chubv]

My concern with that is the double cost as I'll need another once the bike is built and funds are a little tight. Obviously buying the wrong frame is also more expensive. The 56 is quite a lot smaller which scares me!

Did you change the color of the frames in the comparisons?
In the first comparison, the bikes are aligned at the ground, and in the second comparison, they are aligned at the bottom bracket.

[Abreu.T]

https://geometrygeeks.bike/compare/triban-rc500-2019-l,lightcarbon-lcr018-d-2025-54,lightcarbon-lcr018-d-2025-56/

If you atual bike is good you want the numbers bellow to be similiar :

Reach
Stack
Seat Angle
Head Angle

[Westman]

https://geometrygeeks.bike/compare/triban-rc500-2019-l,lightcarbon-lcr018-d-2025-54,lightcarbon-lcr018-d-2025-56/

If you atual bike is good you want the numbers bellow to be similiar :
Reach
Stack
Seat Angle
Head Angle

Thank you very much. That's why I think 56 isn't a stupid choice, even if LightCarbon still want I pick the 54 size. I want something more comfortable/endurance than race/performance.

[JensenMacD]

Thank you very much. That's why I think 56 isn't a stupid choice, even if LightCarbon still want I pick the 54 size. I want something more comfortable/endurance than race/performance.

I don't know your conversation with LC but from what I see regarding stack.

54 is 34mm lower on paper. When you subtract 10mm for bearing cover, 10mm in spacers being suggested and 8mm of bar rise, you are now only 6mm lower.
56 is 16mm lower. Subtract 10mm for bearing cover and 8mm bar rise. You are now 2mm higher.

What are you looking for long term? Are you 100% content with the current Triban position and will NEVER want to go lower in the front end? The 56 will place you slightly higher with the bar slammed. 54 gives you the option to go lower in the future, if you decide. You can also do 15mm of spacers instead of 10mm to get 1mm lower than your current setup.

**Numbers are quick for reference but you would need to do some calculations for the headtube angle, stem angles, stem length and spacers to get it mm perfect.

POTOOOOOOOO really nailed it.

Stack and reach are interlinked - Depending on the amount of spacers you add, you may need a longer stem to compensate.

It’s gets complicated - hence suggesting a pre bike fit.

[Westman]

I don't know your conversation with LC but from what I see regarding stack.

54 is 34mm lower on paper. When you subtract 10mm for bearing cover, 10mm in spacers being suggested and 8mm of bar rise, you are now only 6mm lower.
56 is 16mm lower. Subtract 10mm for bearing cover and 8mm bar rise. You are now 2mm higher.

What are you looking for long term? Are you 100% content with the current Triban position and will NEVER want to go lower in the front end? The 56 will place you slightly higher with the bar slammed. 54 gives you the option to go lower in the future, if you decide. You can also do 15mm of spacers instead of 10mm to get 1mm lower than your current setup.

I'm really comfortable on my Triban right now, and I'm afraid to switch, haha.
But my problem is that I have no experience with a sportier frame, and I've never gone on a ride longer than 2 hours with this Triban.
My stem is 110mm, and I don’t have any spacers on my Triban RC500. On the 54, I’ll have to stack spacers and go with an integrated handlebar that’s 110mm (I can’t adjust the stem), and 100mm on the 56 with no spacers.
This is a long-term decision. I think I can easily adapt to both setups, but what about in 5 or 10 years if my style changes? Which one offers the most flexibility?

[POTOOOOOOOO]

I'm really comfortable on my Triban right now, and I'm afraid to switch, haha.
But my problem is that I have no experience with a sportier frame, and I've never gone on a ride longer than 2 hours with this Triban.
My stem is 110mm, and I don’t have any spacers on my Triban RC500. On the 54, I’ll have to stack spacers and go with an integrated handlebar that’s 110mm (I can’t adjust the stem), and 100mm on the 56 with no spacers.
This is a long-term decision. I think I can easily adapt to both setups, but what about in 5 or 10 years if my style changes? Which one offers the most flexibility?

You’re a novice. 2 hours is not a long ride and even a sub optimal fit won’t show any issues during that time. I also think you’re being a title optimistic when you’re looking 7 years into the future. A bike fit changes as people get injured/ flexibility improves and as the rider changes - ages.

Why don’t you take some advice with a professional fit and set yourself up for success, rather than keep on this journey of guessing? You simply don’t know what you don’t know at this stage in your cycling career.

As a FYI - reach is also effected by bar reach, manufacture of shifter and how they’re positioned - not just stem length.

All of these things need to be accounted for in a bike fit. Any previous injury or physical asymmetry, all make a difference.

Go get fitted - no one can help you anymore than already have.

[Westman]

You're right; I just don't want to spend €250 on a bike fit. I didn't realize that choosing the right bike size was so complicated and personalized.

[POTOOOOOOOO]

They arent all 250 euro. Where are you?