I have S-Works Tarmac SL3 and I really love this bike. However, I'd like to change it to something newer, on electronic groupset.
What is your recommendation/opinion: S-Works Tarmac SL5 or Specialized Expert SL6.
They are available at almost the same price and I am familiar with the differences, but for me there is still no clear answer which one is better.

This is an easy one. The old Tarmac was good but the SL6 is a significant step forward in every way other than aesthetics.

I would like to hear more any specifics on what is significantly better?

I am literally just finishing a build on a 2016 SL5 disc brake Di2 frameset I bought off Ebay. It was a brand new in the original box from Spesh S-works frame set. I got it for a really good price $1250 and I believe he has more if you are interested I can send you his info.

So what I like and don't like about the SL5 disc brake Di2 frameset.

1.The SCS hub spacing and QR skewers made wheel selection difficult. Spesh made this goofy SCS hub and rear derailleur hanger for the disc brake Tarmac that really is unnecessary and confusing. I ended up with a set of CLX40 SCS wheelset but the frameset did come with two derailleurs to run a standard 135mm QR rear hub disc brake wheelset. Most disc brake wheelsets sold are 142mm 12mm TA adn you have to just change the end caps on the hubs to make them 135mm QR, I am pretty sure most wheel manufacturers sell them some include them and if you buy a set of wheels second hand you probably will need to source them.

The Di2 frameset has this tiny ass access hole under the bottom bracket you can't even get your finger tip into so wiring the bike was a chore. I did manage to get all the wires run internally with the 4 port B junction and the EW-WU111 Bluetooth connector all stuffed in there. It wasn't easy and TBH I don't think I can get them back out so lets hope I wont need to.

SL5 disc brake frames use a post mount brake caliper all of the new Shimano stuff is flat mount. Shimano has one post mount caliper the BS-R785 which can be sourced easily BUT, if you want the newer style Di2 shifters with the really cool buttons on the top of the hoods that let you scroll through your Garmin or Wahoo bike computer screens you will have to piece together a groupset and buy the levers without the calipers.

Also the bike originally has 140mm rotors, you can run 160mm with an adapter, I believe most newer bikes use 160mm.

So that is what I ran into building a SL5, the SL6 would have been easier but cost a lot more for the frameset. So far I am really happy with bike I like the way it looks and it is pretty light coming in under 7kg. I hope to have the bike out for its maiden voyage tomorrow. Here is a pic of the bike mocked up along with the ridiculous small access port.

Why didn't you take the bottom bracket out and then sort out the wiring through the big hole on each side?

That was what I was planning to do until I found a youtuber trick using thread and a shop vac. It worked fantastic and I was able to route everything fairly easily. Plus I wanted to avoid pressing it in or out anymore than I have to.

The SCS issue is what keeps me from looking at many older Specialized disc frames. I do believe there is a replacement derailleur hanger to eliminate the SCS issue, but I don't know that it works on all of the frames.

I think the SL6 is gorgeous, but aesthetics are a very personal thing. I'm also a bit biased since I opted for an SL6.

As OHrider mentioned, the SL6 uses the more standard 12x100/12x142 thru axle setup, and flat mount brakes. The Comp/Sport frames also have a threaded bb (Pro/Expert/S-works are press-fit).

Just finished building my SL6 Comp last night, just need to do the bar tape today and take her out for her first ride. I HIGHLY recommend the Park Tool IR-1 internal cable routing kit. The shift cables were actually pretty easy, but we used the IR-1 to route the hyd hoses and it was a lifesaver. I can't even imagine trying to route the rear brake hose without it. We had the whole bike built in a few hours, not even a single swear word was uttered.

I found out about it after I purchased this frame so I had to look into it pretty extensively to figure out what will or wont work. Yes Specialized makes a new derailleur which will allow you to use any 135mm QR rear hub disk brake wheel. My understanding is that almost all new disc brake wheel sets will work if you replace the end caps with QR end caps. Most newer wheelsets will come std with 142mm hub spacing and 12mm TA with the only difference being the end caps, so swapping them to the QR will make the hub spacing 135mm vs 142mm.

The real problem lies with some of the Specialized 12mm thru axle SCS bikes. They do not make a replacement rear derailleur for those bikes and you are stuck using SCS hub rear wheel. I believe this is the Crux and maybe Diverge bikes that are like this. So essentially if you have a frameset with QR skewers and disc brakes all you have to do is swap hangers to run what ever wheels you want.

I ended up with a set of brand new CLX40 tubular SCS wheelset for $500 which I really could not pass up. I originally wanted to run a newer 25c tubeless set up with 21mm/30mm width wheelset but for $500 and a wheelset that is STUPID light I can live with tubs! I can also pass along the dealers info I got those wheels from too if anyone else is looking. Here is latest pic of the bike with a new pair of Corsa Speed G+ all glued up and ready to go. I still have to bleed the brakes and program the Di2 but hope to have it out by the weekend.

I ran into a small snag with the brakes. I am mix matching brake setup with older style calipers and newer levers. Apparently Shimano also changed brake hose from BH59 that the older R785 calipers used to smaller ID BH90 which my new 8070 levers use. From what I can tell the older calipers are compatible with the newer hose so it shouldn't be an issue but we will see.

BTW The local bike shop owner I ride with is selling his size 54 2019 SL6 Sworks Tarmac DA Di2 disc with CLX50 and Sworks dual carbon power cranks for $5k for a complete bike. Its red/white model.

OP I hope this helps you make up your mind on SL5 vs SL6 lol! I am happy with my decision so far but if I were paying more $$ for the frameset I would definitely have gone SL6. Actually I should have just bought my friends bike
that is crazy cheap IMO, to bad I am on a 52cm.

Only one ride on the new SL6, but it is def more responsive than the SL4 that I used to have. Need to get better pictures, but I was losing daylight and needed to get back to the house. lol

The SL6 expert is the cheapest, complete bike, right? Doesn't it have a different seat post, amongst the different frame layup and material? Which means it's frame is not comparable to the other higher sl6 models?

The "Expert" is only one down from the top end S-Works model.
It is a different and heavier carbon lay up but still a great bike.
Personally I would go for the SL6 Expert over the SL5 S-Works.
More comfortable, takes normal wheels, more durable, and any weight penalty would be more than compensated for by the aero gains.

Expert/Pro are the same mold as S-works, just different layup, so there's a lil extra weight. But they have the same design and d-shaped seatpost. The Comp/Sport are a different mold and layup, use a round seatpost, and weigh more than the Expert/Pro. From Specialized the Comp comes with Ultegra (mech or di2) and the Sport with 105.

My Comp fully built with Ultegra r7020 groupset, Zipp SL-70 Aero bars, Zipp stem, carbon seat, Ultegra pedals, DT Swiss ER1600 wheels w/28mm GP5Ks, bottle cages and Wahoo mount is 17.5lbs. Not weight weenie by any means, but I'm happy with it.

Just did the Six Gap Century on it, and it was fantastic. 103 miles, 11,100ft of climbing, comfortable, fast, stable, love it. Doubt you'd be disappointed with one of the higher level options.

First of all, thank you for your comprehensive answer! Honestly, I wasn't aware of the SCS issue as well as caliper/lever stuff. Good to know.
What suprises me on your pictures is a frame colour, in the first picture is more 'torch' than 'red', Probably it does not influence the performance (however as we all know, red bikes are faster), though.
Please send me the info about a seller.

Unfortunately, I need 56/58

SL4 was S-Works or Specialized?

Thank you, but please correct me if I am wrong, isn't the 'PRO' one down from S-Works?

I sent you a listing in a PM, he has one in your size.

The color is more of an orange than red, I like it and think it looks really good against the matte black here are a few pics of it done and in sunlight sorry still just crappy phone pics. I have a couple of rides on it so far and can't be happier it is light, fast and really smooth. The bike came out to 7.28kg with pedals and cage. With the SWAT tire change kit full size spare tubular on the back and Wahoo Element mount and computer and tail light like it is in the pic below it came out to 7.82kg

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It was a Specialized SL4.

The Pro and Expert frames are the same, just different groupsets/wheels. The Pro is positioned under S-Works. It goes:

S-Works
Pro
Expert
Comp
Sport

But there are only three frames, S-Works, Pro/Expert, Comp/Sport.

BTW the the Roval CLX40's I got were NOT SCS hubs, I had to swap the rear derailleur hanger over to the std one and it works just fine with zero chain-line issues. The frameset will come with two RD hangers one SCS and one Std. Chuck the SCS and use the std it will fit any 135mm QR disc brake hub wheel and almost all 142mm TA disc brake wheels can be converted to 135 QR by just changing the end caps.

Just to summarize this thread, It tooks me over 2 months, I was about to buy SW SL6 rim, however ended up with S-Works Tarmac SL5 Disc for ~3600$ with Ultegra Di2 6870, Roval CLX40 and Quark PM. Honestly, I would never have expected that it is such a big difference! The bike just goes faster and handles betters. For Di2 and discs, as one said, there is no way back. Even for Campa evangelist.Thank you all again for your opinions!
After a bikefit, I had to change stem from S-Works SL to FSA K-Force OS99 and saddle to S-Works Toupe from Fizik Antares, that's why the bike on pics differs a bit.

I had a S-works Tarmac 2006 and drilled the frame and installed DA DI2 over the year I was collecting parts for a new bike. I had trouble finding a 2019 or 18 SL6 (NO DISKS) in the color I wanted. I finally settled for Chameleon with Enve SES bars max slammed, Zip sprint dropped stem, Selle I SuperLeggra saddle and Boyd 60's PT. Noticeably softer ride than the 06' Tarmac and faster acceleration. Love it. The direct mount brakes are way more than adequate and this thing is light as a feather.

Bike looks awesome good job that is a lot of bike for $3600. I couldn't agree more I can't believe how much better this bike does at just about everything over my old road bike. Did you get the frameset from the guy I sent you on ebay?

To bad it is winter got the bikes all stuff away and put my old road bike on the Kickr Zwift season lol.

Thank you, as for the seller, unfortunately he does not send to Europe. I was constantly checking offers in the internet and found the complete bike in recommended shop. I saw your post on weightweenies and I am impressed with the weight of your bike!
My is about 7.7kg, without a saddlebag. I have to go through your listing to find the differences.

From what I can see the biggest two would be I am on a 52cm frame and my CLX40's are tubular and they are really light. Smaller differences would be the newer Ultegra Di2 is lighter than the 6800 especially the shifters which I think is 120g difference. I am also running a really light saddle and seat post. Pro-vibe aero bar is only 200g and is a 40cm, small stuff but as you know it adds up. Still 7.7kg is pretty light.

Congrats on new bike hope you can ride it more this winter than I will be in Ohio. I have about 300 miles on it so far and have really enjoyed riding it and cant wait till spring.