Signature Series Smooth Rider Seat and Backrest

Part Number 51998-08


Finish / Color: Black



The perfect combination of foam density and shape has created our most comfortable seat for long-haul touring. Both rider and passenger will be comfortable riding to Sturgis and back with wide seating area.

  • Smooth styling
  • Seat features an easily removable adjustable rider backrest that folds down for easier passenger mounting
  • Rider backrest has a 5-position height adjustment with 1.5" range
  • Wide range of forward/back angle adjustment with the quick twist of the control knob
  • Seat width 16.0"
  • Stop by a participating dealer and test out this seat today as part of our Seat Demo Program –
    contact your local dealer for details


Fits '00-'17 FLST, FLSTC, FLSTNSE and FLSTSC, '00-'06 FLSTF and '00-'05 Softail® models (except FXSTD). Also fits FLSTN models with removal of stock luggage rack. '00-'06 FLST, FLSTC, FLSTF, FLSTSC and '00-'05 FX Softail® models require separate purchase of Seat Bracket P/N 51949-09. Seat width 16.0"; passenger pillion width 14.0".

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  • Model
  • Adjustable

  • Material Content

  • Seat Width

    16.0 Inch
  • Pillion Width

    14.0 Inch
  • Warranty

    1 year limited warranty – Go to for full details
  • Sold in Unit

  • In The Box

    Rider backrest, grab strap, seat bracket, and all necessary mounting hardware
Signature Series Smooth Rider Seat & Backrest is rated 4.3 out of 5 by 6.
Rated 4 out of 5 by from Check mounting hardware No complaints about the seat(need to install air deflector), however, the front mounting screw for the rear mounting bracket has scribed a circle thru the rear fender paint working it's way thru the fender. Perhaps reducing the screw head profile will solve this issue.
Date published: 2017-10-16
Rated 2 out of 5 by from Signature series seat with backrest The Harley store did not have one for me to try. Put my trust in Harley and ordered the seat. I love the back rest and the passenger seat is larger than my original. The rider seat is not as comfortable as the original. A 30-40 minute ride finds me adjusting my position. For the price, I'm disappointed.
Date published: 2017-09-09
Rated 5 out of 5 by from SIGNATURE SERIES SMOOTH RIDER SEAT & BACKREST I love this seat! Right after installing this seat I took a 350 mile ride. It was comfortable the entire trip.
Date published: 2015-09-09
Rated 5 out of 5 by from Great comfort Bought a 2014 Heritage last year and my butts been hurting since then. Bought the Signature series and decided on hour 3 of my first ride that this should probably be the stock seat Harley puts on their bikes. I love the look of a bike, but if you're butt hurts after 30 minutes, it's a waste. I'm taking this seat on a 32 hour ride next week and I was dreading it. With the signature series, I can't wait to get on the road. I love this seat and would recommend to everyone.
Date published: 2015-04-11
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Does this seat move the rider forward once installed?

The signature series seat with the studs got several reviews that once installed they felt like they had been moved forward. Is there a structural difference between the two seats?
Asked by: davidnelson68w
Yes it does put you forward. for me it was 2 to 3 inches more forward than the stock seat
Answered by: Skypiper
Date published: 2017-10-21

Rider backrest, does it fold down to allow rider ease to get on and off? or, does it just fold forward for passenger ease?

Does the seat fold down to allow rider ease of getting on and off, or just fold forward for rider to get on and off easier?
Asked by: OLDHOG

Older vs newer Heritage Softail fitment

Is there a different part number for this Signature Series Smooth Rider Seat & Backrest if it is for a 2002 Heritage Classic vs ones 2007 and newer? And what is the part number for the one that fits the 2002? thanks
Asked by: RadarLover777
Hey RadarLover777, The Signature Series Smooth Rider Seat and Backrest-51998-08 is validated to fit 2000 and later FLSTC models. For an '02 you'll need the Seat Bracket P/N 51949-09 as well. Thanks! Rockstar883
Answered by: Rockstar883
Date published: 2016-09-01

what is the difference between the smooth and the series with studs on the signature series seat?

Asked by: Jerry39
Hi Jerry39, Both-- **Seat features an easily removable, adjustable rider backrest that folds down for easier passenger mounting. **Rider backrest has a 5-position height adjustment with 1.5" range. **Wide range of forward/back angle adjustment with the quick twist of the control knob. **Seat width 16.0" Smooth Series-- The Smooth Series provides the passenger and rider with an authentic leather look. No decorative features--just leather. No age lines or creases are present to give it an aged look. Styling Series-- The Styling Series provides bling where bling is needed. Passenger and rider can enjoy having a classic look w/studs to enhance the basic leather seat. The studs can be found on the passenger/rider backrest, seat and saddlebags (sold separately).
Answered by: RowdyGrl79
Date published: 2016-12-29

The Signature Series Seat for the Softail has a rider backrest, I didn't know how to remove it, figured it out, and maybe can save others some time.

If you look on the web page, under more info, you will see a link that takes you to the instructions that come with the seat. The instructions don't detail installation and (critically) removal of the rider's backrest. This is a problem, if you install the backrest without knowing how to remove it! Take my word for it. I read other sources for supposedly similar seats showing (for example the Signature Series sols seat) that you press down and twist to install the rider's backrest. If so the opposite must uninstall it, right? Also else where it is stated there are tabs on the sides of the post and you manipulate them. Nope. Nope. Neither method applies in the Signature Series seat (two up) for Softails, circa 2016. Instead, do this. Go to the front surface of the post that the backrest pad is attached to, and slide your finger into the seat and down that front surface of the backrest post.(Figure 3, in the instructions, shows this, and the item you are sliding down is named the main pivot, but it is the post. Take my word for it!) As you slide your finger down this post, you press on that front surface, so you are pushing on the front surface of the post, pressing toward the rear of the bike. You don't realize it at the moment, but you will actually be depressing a small piece of spring steel which, when not depressed causes the post to be retained by hardware within the seat. Continue to press and at the same time now lift upwards, on the backrest, like you are attempting to pull the backrest out of the seat (because you are!). The backrest will release and easily be removed. Now, you can examine the surface you pressed and see how it works. Which, unlike me, if you were smart, you did before you slid the backrest into the seat and heard that awful click.
Asked by: Rob44
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    Prices listed are generally the Manufacturer's Suggested Retail Price (MSRP), excluding taxes and shipping. Prices at local dealerships may vary. All online orders will be fulfilled and shipped by
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