# Tarmac 58 Geometry Changing



## Scott in MD (Jun 24, 2008)

I traded the following notes with Spesh this week (later December, 2011) regarding size 58 geometry ... it seems like the Tarmac SL4 is lower and longer than the SL3. 


Me:
Hey guys, I have a 2008 size 58 Tarmac. Love it. Fits perfect. Looking at new SL4 Tarmac and notice in size 58 the head tube is lower (190mm SL4 versus 205mm on legacy Tarmacs) but stack and reach are same (591 & 402). Is this correct? New 58 SL4 is same stack and reach as SL3 and previous models? Just checking before some test rides. Thanks.

Specialized Bicycles:
Hi, Scott. There are some subtle differences in the measurements between Tarmac SL3 and SL4. (turns out the info on Specialized.com needs to be updated...we're on it). Here are the correct stack/reach numbers for each in size 58cm. Tarmac SL3: 607 stack, 397 reach. Tarmac SL4 (and Venge): 591 stack, 402 reach. Hope this helps!


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## PJ352 (Dec 5, 2007)

Scott in MD said:


> I traded the following notes with Spesh this week (later December, 2011) regarding size 58 geometry ... *it seems like the Tarmac SL4 is lower and longer than the SL3. *
> 
> 
> Me:
> ...


Thanks for sharing this...

Yes, considering how frame stack and reach are measured, it would follow that both numbers have to change with the HT length change. If you visualize a shorter/ taller HT in the illustration below, you can see how (given the HT angle) _reach_ lengthens/ shortens and _stack_ lowers/ raises respectively.
View attachment 248041

FWIW, I noticed that not all sizes have been altered.


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## Scott in MD (Jun 24, 2008)

WHen I first saw that head tube on Venge was 190mm, I thought "Yep, now Spesh has an aero-pro fit on the Venge, a performance-race fit on the Tarmac (205mm) and a performance-comfort fit on the Roubaix (225mm). But this change seems to indicate that, at least for size 58, there will be a gap in sizing between Venge /Tarmac and Roubaix of 35mm (almost 1-1/2 inches). I am not sure how I feel about this, but it's all about the ride so I'm going to give it a try. But my first impression is that the 205mm HT and 607mm of stack on the SL3 is a better fit for me.


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## PJ352 (Dec 5, 2007)

Scott in MD said:


> WHen I first saw that head tube on Venge was 190mm, I thought "Yep, now Spesh has an aero-pro fit on the Venge, a performance-race fit on the Tarmac (205mm) and a performance-comfort fit on the Roubaix (225mm). But this change seems to indicate that, at least for size 58, there will be a gap in sizing between Venge /Tarmac and Roubaix of 35mm (almost 1-1/2 inches). I am not sure how I feel about this, but it's all about the ride so I'm going to give it a try. But *my first impression is that the 205mm HT and 607mm of stack on the SL3 is a better fit for me*.


Depends on your current setup, but you may want to play with some numbers before deciding. If you want to post them, we'll be able to at least get you close to knowing what the HTL's would mean to you. 

Going back literally decades, one of the mistakes I think a number of manufacturers made when going to integrated headsets is NOT elongating HT's to compensate. My 52cm steel framed bike has a HT length of 110mm's and a headset upper stack height of 3cm's, for an effective total of 140mm's. My 52cm Tarmac's HTL is 120mm's and once a steerer tube is cut, the difference can only be made up with changes to stem angle - basically flipped up. 

I've always said that bars are easier to drop than raise, and for recreational/ fitness riders comfortable with a moderate (~5.5cm) drop to bars (me), even adding 10mm's to that 120mm HTL would help.


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## roadworthy (Nov 11, 2011)

Scott in MD said:


> WHen I first saw that head tube on Venge was 190mm, I thought "Yep, now Spesh has an aero-pro fit on the Venge, a performance-race fit on the Tarmac (205mm) and a performance-comfort fit on the Roubaix (225mm). But this change seems to indicate that, at least for size 58, there will be a gap in sizing between Venge /Tarmac and Roubaix of 35mm (almost 1-1/2 inches). I am not sure how I feel about this, but it's all about the ride so I'm going to give it a try. But my first impression is that the 205mm HT and 607mm of stack on the SL3 is a better fit for me.


Funny how mfr's tweak head tube lengths over time. I always loved the Tarmac headtube length and geometry...one of the things I always liked about the bike...a racing bike with a comfortable performance fit. I ride mostly 58cm bikes as well. Having the Roubaix now with monster head tube  I am now in the sweet spot of my adjustment as I don't like to ride with a lot of drop which is a true dilemma for a guy like me with 35" inseam at just over 6' tall. I thank Specialized for the Roubaix as it is really a perfect fit for a guy with long legs...whereas most conventional or closer to square geometries tend to yield a lot of drop for guys that have longer legs. So there is really a parallel universe when it comes to fit for a 6'er who would seek a size 58...guys with short legs and guys with long legs really fit much different on a given frame size even if the same height. I have a friend who is the same height as me and he is all torso. He rides with his saddle a full 2 inches lower than me and of course he therefore prefers a proportionately shorter head tube. So Specialized reducing heat tube height on the Tarmac will please the aggressive fit and/or short legged crowd and displease those with either long legs or prefer to ride a bit more upright.

And then you have Cervelo moving in the opposite direction with their R-series bike which has created quite a backlash within the slammed, go fast community of riders. A fair amount of outcry has been incited by making a 58cm R3/R5 now with 199mm head tube....all the way up from a 180mm previously. Cervelo did this of course based upon customer feedback...guys running a lot of spacers to be comfortable who would prefer a more racey looking bike with fewer or no spacers. 

So the move by both top brands goes both ways and won't please everybody. Cervelo's move to lengthen R-series head tubes puts it in the mix for a guy like me now however and move the Tarmac more away from the fit I prefer. S-series Cervelo's have short head tubes which appeal to short legged guys or those that like to ride with more drop which btw is what my buddy rides who is all torso.


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## ukbloke (Sep 1, 2007)

I wonder if Specialized has done this to compensate for the demise of the "team geometry" models? I can imagine that there are many amateur racers and some pro racers that need the 58 model, but would be badly served by the previous 205mm head tube. This compares with 170mm on the team geometry frame, and one can imagine that a racer on that frame would be pretty upset about increasing by 35mm and trying to compensate with stem. Many would have had their stem slammed even on the team geometry frame. The new 190mm sizing splits the difference between these. It always seems to me that the head tube scaled up too dramatically from the 56 to 58 to the 61. So I think this is a reasonable change, even though I ride a 58 and the 205mm turned out to be near ideal for me, and for those who need the extra head tube length there's always the Roubaix.


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## roadworthy (Nov 11, 2011)

ukbloke said:


> I wonder if Specialized has done this to compensate for the demise of the "team geometry" models? I can imagine that there are many amateur racers and some pro racers that need the 58 model, but would be badly served by the previous 205mm head tube. This compares with 170mm on the team geometry frame, and one can imagine that a racer on that frame would be pretty upset about increasing by 35mm and trying to compensate with stem. Many would have had their stem slammed even on the team geometry frame. The new 190mm sizing splits the difference between these. It always seems to me that the head tube scaled up too dramatically from the 56 to 58 to the 61. So I think this is a reasonable change, even though I ride a 58 and the 205mm turned out to be near ideal for me, and for those who need the extra head tube length there's always the Roubaix.


I would agree...even though the move isn't directionally correct for someone who prefers a more upright fit, the Tarmac is a race bike and the Roubaix is positioned toward those who want to ride in a bit more relaxed position. No doubt that many that purchase a Tarmac will appreciate the new geometry and will appeal to larger demographic of Tarmac rider.


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## PJ352 (Dec 5, 2007)

ukbloke said:


> ... for those who need the extra head tube length there's always the Roubaix.


Trouble is, some (like me) prefer Tarmacs handling to Roubaix's, so the trade off (at least for me) isn't a worthwhile one. As I mentioned earlier, a 1cm increase in my Tarmac's HTL would help, but 'as is' I'm running a 100mm, -8* stem with 35mm's of spacers, so a very 'moderate' setup. 

Conversely, I think the OP in the 'stem' thread has some notable issues/ compromises that need to be made to get an adequate setup on his Tarmac. In that case I think I'd consider a Roubaix (or similar).


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