Seraph Bikes Superlight 836g X68 - Alternative to SL8 Fakes?

[Bonus79]

Hello to all
Here is my contribution to all X68 fans.
Currently I have 2 X68's at home. Specifications below:

Frame: X68 size 44
Handlebars: Seraph Carbon handlebar 36cm
Wheelset: Farsports 40mm with Carbon spokes
Groupset: Shimano 105 Di2 12 speed
Crankset: Shimano 105 50/34, 170mm
Chain: Shimano 105 12 speed
Casette: 16-30 Shimano / Miche (for my son's race limitation)
Saddle: Ryet
Pedals: Shimano Ultegra
Tires: Continental GP5000 30mm
Tubes: Tubolito TPU
Bike weight: 7.0 KG !

Frame: X68 size 56
Handlebars: Seraph Carbon handlebar 36cm
Wheelset: Zen Wheels  50mm with Carbon spokes (1.145g)
Groupset: Shimano Ultegra Di2 12 speed
Crankset: Shimano  Ultegra  52/36, 170mm
Chain: KMC black 12 speed
Casette: Goldfix 11-34 black
Saddle: Berk Lipa
Pedals: Assioma UNO
Tires: Continental GP5000 30mm
Tubes: Tubolito TPU
Bike weight: 6,95kg

Regarding assembly: none of above 2 bikes have/had any issue at all. Neither with cable routing, neither with facing of brake calippers.  The guy that assemblied bikes was actually impressed about the quality of the frame. He stated, that many original brands are much worse in terms of assembly.
On 1st bike stem bolts were oxidised after 2-3 rides and they have sent me replacement.
On 2nd bike, they have sent me silver stem screw which really does not fit to black handlebar. But also that was replaced by them as well.
One more thing that is noticable is that both bikes were ordered same color (white pearl) but mine is far more »snow« white than my son's. Paint guy must have had bad day=) But still, they both look great.
Regarding ride & handling:
The 44 size bike was used by my son. He did aprox 4.000km in 2025, mostly racing. He even crashed 3 times this season, but there is no damage to the frame at all (not counting small scratch at rear axle:/)

I owned  S-works Tarmac SL5 disc before. Meaning I am not switching from some bad bike to X68, but still the difference is noticable.
X68 is more stiff (probably also due to thruaxle system instead of QR and SL5 being used for 9 seasons) especially in front end, but at the same time also more comfortable (also switch from 25mm to 30mm tyres does the job).

Haven't done many rides yet, so that's what I can tell so far.
 Feel free to ask if you have any more specific questions

Hi, congratulations on the bikes, very nice!
Can I ask you the saddle height and saddle-to-handlebar drop on your 56?
I've started building my Spcycle R088...it has a very similar color scheme to yours, but I opted for an off-white with a marbled effect. 

[Bugo]

Hi
Not Sure what this measurments will benefit you, but here are details of my position on bike:

[Jaaniusss]

I've started building my Spcycle R088...

Those spacers look borderline criminal

[Sander2177]

Those spacers look borderline criminal

It’s all about the high stack  for aero didn’t you know

[Bonus79]

Hi
Not Sure what this measurments will benefit you, but here are details of my position on bike:

We have very similar measurements, so the aesthetic result will be very similar, thank you. 

[Bonus79]

Those spacers look borderline criminal

Right....but I still have to cut the fork! 
When finished, I should have 20-25mm of spacers under the handlebars.
Unfortunately, the top headset cap doesn't fit the frame well and is left protruding from the frame, exposing the top bearing. The diameter is fine (57mm), but the fork hole isn't centered on the head tube hole, so I need to find another cap compatible with the frame and the Elita One handlebars, such as the Roval Rapide.

[Bonus79]

Those spacers look borderline criminal

These could be the final settings....but before cutting the fork above the handlebars I want to finish assembling the frame and do some tests first. 

[naiboo]

I'm struggling with the sizing of the x68 / SL8 and seeking advice. I´m 178cm and inseam of 82cm. Saddle height from center bb to top of the saddle is atm 76cm and stem 110.
I currently ride a Scott Addict 20 2015 and a Scott Speedster Gravel 2023, both in 54. Both fit nicely and to be fair i've mainly ridden the gravel lately and love it. https://geometrygeeks.bike/compare/tantan-tt-x68-2024-54,tantan-tt-x68-2024-56,scott-addict-10-2015-54,scott-speedster-gravel-20-2023-m54/

According to SL8 sizing i fall exactly between 54 and 56. I tend to go to a 54 atm but i fear that it is too agressive and need a spacer stack of ~2cm to fit me well.

Any suggestions are highly appreciated.

[Bonus79]

I'm struggling with the sizing of the x68 / SL8 and seeking advice. I´m 178cm and inseam of 82cm. Saddle height from center bb to top of the saddle is atm 76cm and stem 110.
I currently ride a Scott Addict 20 2015 and a Scott Speedster Gravel 2023, both in 54. Both fit nicely and to be fair i've mainly ridden the gravel lately and love it. https://geometrygeeks.bike/compare/tantan-tt-x68-2024-54,tantan-tt-x68-2024-56,scott-addict-10-2015-54,scott-speedster-gravel-20-2023-m54/

According to SL8 sizing i fall exactly between 54 and 56. I tend to go to a 54 atm but i fear that it is too agressive and need a spacer stack of ~2cm to fit me well.

Any suggestions are highly appreciated.

Are you sure the measurements you provided are correct?
I'm 180cm tall, with an inseam of 87cm, and a saddle height of 76.5cm...

[Bugo]

Naiboo, keep in mind that you can always extend position (seat back, longer stem)  on 54, whereas on 56 (if it's too big) you are in difficult position.
The seatpost  on X68 has 2cm offset. First check this on your existing bike. Then try to catch same reach with stem length.

example: I had size 56 SL5 with 0 offset + 10cm stem. The saddle was in the middle of rails.
              I took size 56 X68 with 9cm stem and seat is moved maximum to the front. And this positions is exactly the same as on SL5. So I have no margin anymore, but it fits me perfect. 

I suggest you to take 54 and adjust stem length and move the saddle accordingly.

[glepore]

Are you sure the measurements you provided are correct?
I'm 180cm tall, with an inseam of 87cm, and a saddle height of 76.5cm...

I fell exactly between a 49 and 52. I went with the 49 for a couple reasons, mainly that I think slightly smaller frames feel more nimble and lively under me, and because it allowed for a 110 stem to get the reach I wanted (my experience with short stems has been that they effect steering feel and to some extent stability). My fear was that the greater drop would be an issue. Its not. I do have to run all the spacers, but it doesn't look bad and the bike feels great, is nimble, and I don't have any stability issues downhill at speed despite deep wheels.

[crazyravr]

General rule if in between sizes, always go smaller. Always.

[Bonus79]

I fell exactly between a 49 and 52. I went with the 49 for a couple reasons, mainly that I think slightly smaller frames feel more nimble and lively under me, and because it allowed for a 110 stem to get the reach I wanted (my experience with short stems has been that they effect steering feel and to some extent stability). My fear was that the greater drop would be an issue. Its not. I do have to run all the spacers, but it doesn't look bad and the bike feels great, is nimble, and I don't have any stability issues downhill at speed despite deep wheels.

Hi, I was referring to the fact that with an 82cm inseam, a 76cm saddle height seems a lot to me...since I pedal more or less at the same height, but with an extra 5cm inseam.

[OlHag Cyclismo]

I'm struggling with the sizing of the x68 / SL8 and seeking advice. I´m 178cm and inseam of 82cm. Saddle height from center bb to top of the saddle is atm 76cm and stem 110.
I currently ride a Scott Addict 20 2015 and a Scott Speedster Gravel 2023, both in 54. Both fit nicely and to be fair i've mainly ridden the gravel lately and love it. https://geometrygeeks.bike/compare/tantan-tt-x68-2024-54,tantan-tt-x68-2024-56,scott-addict-10-2015-54,scott-speedster-gravel-20-2023-m54/

According to SL8 sizing i fall exactly between 54 and 56. I tend to go to a 54 atm but i fear that it is too agressive and need a spacer stack of ~2cm to fit me well.

Any suggestions are highly appreciated.

We're the same height, I've only ever ridden size 54 frames. I ride a 120 stem and use 20mm of spacers. Absolutely no issue with my fit on this bike. 56 would probably feel like a tractor if you've only ever ridden 54's. Just my two cents

[OrbisNonSufficit]

Assembly completed and first 30km ride.
Size 52
Ultegra di2
RD Hanger + Upgraded bolts from tiparts
2 sets of wheels: Serenade wheels 55 wave and Alpha wheels tubular with tune hub (on the picture)
BB ceramic from nova ride
Crankset and chainring 52-36, 165mm with power meter from magene.
Old saddle and bottle cages.

Next upgrades:

Lighter saddle and bottle cages.
Change the garmin support which feels really cheap.

Around 3200euros for the complete build. I include the cost of the tools for disc brakes.